Misha and Vanya have played several table tennis sets. Each set consists of several serves, each serve is won by one of the players, he receives one point and the loser receives nothing. Once one of the players scores exactly k points, the score is reset and a new set begins.

Across all the sets Misha scored a points in total, and Vanya scored b points. Given this information, determine the maximum number of sets they could have played, or that the situation is impossible.

Note that the game consisted of several complete sets.

Input

The first line contains three space-separated integers k, a and b (1 ≤ k ≤ 109, 0 ≤ a, b ≤ 109, a + b > 0).

Output

If the situation is impossible, print a single number -1. Otherwise, print the maximum possible number of sets.

Examples

Input

11 11 5


Output

1


Input

11 2 3


Output

-1

Note

Note that the rules of the game in this problem differ from the real table tennis game, for example, the rule of "balance" (the winning player has to be at least two points ahead to win a set) has no power within the present problem.
#include <bits/stdc++.h>
namespace algo {
using std::swap;
const long double PI = 3.141592653589793238462643383279502884L;
const long double E = 2.718281828459045235360287471352662498L;
const long double EPS = 1e-12L;
template <typename T1, typename T2>
T1 bin_pow(T1 a, T2 n) {
  T1 r{1};
  while (n > 0) {
    if (n % 2 == 1) r *= a;
    a *= a;
    n /= 2;
  }
  return r;
}
template <typename T1, typename T2>
T1 bin_pow(T1 a, T2 n, const T1& m) {
  if (m == 1) return 0;
  T1 r{1};
  while (n > 0) {
    if (n % 2 == 1) {
      r *= a;
      r %= m;
    }
    a *= a;
    a %= m;
    n /= 2;
  }
  return r;
}
std::string to_roman(int n) {
  static std::string d[3][10] = {
      {"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"},
      {"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"},
      {"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"}};
  std::string res(n / 1000U, 'M');
  n %= 1000;
  return res + d[0][n / 100] + d[1][n / 10 % 10] + d[2][n % 10];
}
int from_roman(const std::string& n) {
  auto to_int = [](char c) -> int {
    switch (c) {
      case 'I':
        return 1;
      case 'V':
        return 5;
      case 'X':
        return 10;
      case 'L':
        return 50;
      case 'C':
        return 100;
      case 'D':
        return 500;
      case 'M':
        return 1000;
      default:
        return 0;
    }
  };
  int r = 0, p = 0;
  for (auto it = n.rbegin(); it != n.rend(); ++it) {
    int inc = to_int(*it);
    r += inc < p ? -inc : inc;
    p = inc;
  }
  return r;
}
template <typename T>
T gcd(const T& a, const T& b) {
  if (b == 0) return a < 0 ? -a : a;
  return gcd(b, a % b);
}
template <typename T>
T gcd(const T& a, const T& b, T& x, T& y) {
  if (b == 0) {
    x = a < 0 ? -1 : 1;
    y = 0;
    return x * a;
  }
  T d{gcd(b, a % b, y, x)};
  y -= (a / b) * x;
  return d;
}
template <typename T>
T lcm(const T& a, const T& b) {
  T r{a / gcd(a, b) * b};
  return r < 0 ? -r : r;
}
template <typename T>
T mod_add(const T& a, const T& b, const T& m) {
  if (a < m - b) return a + b;
  return a - (m - b);
}
template <typename T>
T mod_sub(const T& a, const T& b, const T& m) {
  if (a < b) return a + (m - b);
  return a - b;
}
template <typename T>
T mod_mul(T a, T b, const T& m) {
  if (b > a) swap(a, b);
  T r{0};
  while (b > 0) {
    if (b % 2 == 1) r = mod_add(r, a, m);
    a = mod_add(a, a, m);
    b /= 2;
  }
  return r;
}
template <typename T1, typename T2>
T1 mod_pow(T1 a, T2 n, const T1& m) {
  if (m == 1) return 0;
  T1 r{1};
  while (n > 0) {
    if (n % 2 == 1) r = mod_mul(r, a, m);
    a = mod_mul(a, a, m);
    n /= 2;
  }
  return r;
}
template <typename T>
T mod_inv(const T& a, const T& m) {
  T x, y;
  T d{gcd(a, m, x, y)};
  if (d != 1) return 0;
  if (x < 0) x += m;
  return x;
}
std::vector<int32_t> gen_inv(int32_t m) {
  std::vector<int32_t> r(static_cast<size_t>(m));
  if (m > 1) {
    r[1] = 1;
    for (int i = 2; i < m; ++i)
      r[i] = (m - static_cast<int32_t>((m / i) * 1LL * r[m % i] % m)) % m;
  }
  return r;
}
void mul_u128(uint64_t a, uint64_t b, uint64_t& lo, uint64_t& hi) {
  asm("mulq %3" : "=a"(lo), "=d"(hi) : "a"(a), "rm"(b));
};
uint64_t mul_mod_u64(uint64_t a, uint64_t b, uint64_t m) {
  if (a >= m) a %= m;
  if (b >= m) b %= m;
  uint64_t r, u;
  asm("mulq %3\n\tdivq %4"
      : "=a"(u), "=&d"(r)
      : "a"(a), "rm"(b), "rm"(m)
      : "cc");
  return r;
}
template <typename T>
T phi(T n) {
  T t = std::sqrt(n) + EPS;
  T r = n;
  for (T i = 2; i <= t; ++i) {
    if (n % i == 0) {
      r -= r / i;
      do {
        n /= i;
      } while (n % i == 0);
      t = std::sqrt(n) + EPS;
    }
  }
  if (n > 1) r -= r / n;
  return r;
}
class LinearPhi {
 public:
  LinearPhi(uint32_t n = 1 << 20) : size_{n} {
    assert(size_ > 0 && "Size should be nonzero");
    assert(size_ <= INT32_MAX && "Size should fit into an 32-bit signed int");
    uint32_t sz = (size_ + 1) / 2;
    phi_ = new int32_t[sz];
    mark_.assign(sz, false);
    phi_[0] = 1;
    if (size_ > 1) primes_.push_back(2);
    for (uint32_t i = 1; i < sz; ++i) {
      uint32_t val = i << 1 | 1;
      if (!mark_[i]) {
        phi_[i] = val - 1;
        primes_.push_back(val);
      }
      if (val < sz) {
        for (uint32_t j = 1; j < primes_.size(); ++j) {
          uint32_t t = val * primes_[j];
          if (t > size_) break;
          mark_[t >> 1] = true;
          if (val % primes_[j] == 0) {
            phi_[t >> 1] = phi_[i] * primes_[j];
            break;
          }
          phi_[t >> 1] = phi_[i] * (primes_[j] - 1);
        }
      }
    }
  }
  LinearPhi(const LinearPhi&) = delete;
  LinearPhi& operator=(const LinearPhi&) = delete;
  ~LinearPhi() {
    delete[] phi_;
    phi_ = nullptr;
  }
  const uint32_t& size() const { return size_; }
  int32_t phi(int32_t i) const {
    int32_t r = 1;
    int k = __builtin_ctz(i);
    if (k > 0) {
      i >>= k;
      r <<= k - 1;
    }
    return r * phi_[i >> 1];
  }
  int32_t operator[](int32_t i) const { return phi(i); }
  const std::vector<int32_t>& primes() const { return primes_; }

 private:
  int32_t* phi_ = nullptr;
  std::vector<bool> mark_;
  uint32_t size_;
  std::vector<int32_t> primes_;
};
class Sieve {
 public:
  Sieve(uint32_t n = 1 << 20) : size_{n} {
    assert(size_ > 0 && "Size should be nonzero");
    assert(size_ <= INT32_MAX && "Size should fit into an 32-bit signed int");
    uint32_t sz = (size_ + 1) / 2;
    prime_.assign(sz, true);
    prime_[0] = false;
    for (uint32_t i = 1; i < sz; ++i) {
      uint32_t val = i << 1 | 1;
      if (prime_[i] && val * 1ULL * val <= size_)
        for (uint32_t j = val * val; j <= size_; j += 2 * val)
          prime_[j >> 1] = false;
    }
  }
  Sieve(const Sieve&) = delete;
  Sieve& operator=(const Sieve&) = delete;
  const uint32_t& size() const { return size_; }
  bool isPrime(const int32_t& i) const {
    if (i % 2 == 0) return i == 2;
    return prime_[i >> 1];
  }
  bool operator[](const int32_t& i) const { return isPrime(i); }

 private:
  uint32_t size_;
  std::vector<bool> prime_;
};
class LinearSieve {
 public:
  LinearSieve(uint32_t n = 1 << 20) : size_{n} {
    assert(size_ > 0 && "Size should be nonzero");
    assert(size_ <= INT32_MAX && "Size should fit into an 32-bit signed int");
    uint32_t sz = (size_ + 1) / 2;
    lpf_ = new uint16_t[sz];
    std::fill(lpf_, lpf_ + sz, 0);
    lpf_[0] = 1;
    if (size_ > 1) primes_.push_back(2);
    for (uint32_t i = 1; i < sz; ++i) {
      uint32_t val = i << 1 | 1;
      if (!lpf_[i]) primes_.push_back(val);
      if (val < sz) {
        for (uint32_t j = 1; j < primes_.size(); ++j) {
          uint32_t t = val * primes_[j];
          if (t > size_) break;
          lpf_[t >> 1] = static_cast<uint16_t>(primes_[j]);
          if (lpf_[t >> 1] == (lpf_[i] ? lpf_[i] : val)) break;
        }
      }
    }
  }
  LinearSieve(const LinearSieve&) = delete;
  LinearSieve& operator=(const LinearSieve&) = delete;
  ~LinearSieve() {
    delete[] lpf_;
    lpf_ = nullptr;
  }
  const uint32_t& size() const { return size_; }
  bool isPrime(const int32_t& i) const {
    if (i % 2 == 0) return i == 2;
    return !lpf_[i >> 1];
  }
  bool operator[](const int32_t& i) const { return isPrime(i); }
  int32_t lpf(const int32_t& i) const {
    if (i % 2 == 0) return 2;
    if (!lpf_[i >> 1]) return i;
    return lpf_[i >> 1];
  }
  int32_t phi(int32_t i) const {
    int32_t r = 1;
    int k = __builtin_ctz(i);
    if (k > 0) {
      i >>= k;
      r <<= k - 1;
    }
    int32_t n, t = lpf_[i >> 1] ? lpf_[i >> 1] : i;
    while (t != 1) {
      r *= (t - 1);
      i /= t;
      n = lpf_[i >> 1] ? lpf_[i >> 1] : i;
      while (n == t) {
        r *= n;
        i /= t;
        n = lpf_[i >> 1] ? lpf_[i >> 1] : i;
      }
      t = n;
    }
    return r;
  }
  const std::vector<int32_t>& primes() const { return primes_; }

 private:
  uint16_t* lpf_ = nullptr;
  uint32_t size_;
  std::vector<int32_t> primes_;
};
bool isSprp(uint32_t n, uint32_t a) {
  uint32_t d = n - 1;
  int s = __builtin_ctz(d);
  d >>= s;
  uint64_t b = a, r = 1;
  while (d > 0) {
    if (d & 1) r = (r * b) % n;
    b = (b * b) % n;
    d >>= 1;
  }
  if (r == 1) return true;
  b = n - 1;
  for (int i = 1; i < s; ++i) {
    if (r == b) return true;
    r = (r * r) % n;
  }
  return r == b;
}
bool isSprp(uint64_t n, const std::vector<uint64_t>& v) {
  auto mont_u64_mod_n = [&]() -> uint64_t {
    if (n <= (1ULL << 63)) {
      uint64_t res = ((1ULL << 63) % n) << 1;
      return res < n ? res : res - n;
    }
    return 0ULL - n;
  };
  auto mont_inv = [&]() -> uint64_t {
    uint64_t j, s = 1;
    uint32_t i, t;
    static const uint8_t masks[128] = {
        255, 85,  51,  73,  199, 93,  59,  17,  15,  229, 195, 89,  215,
        237, 203, 33,  31,  117, 83,  105, 231, 125, 91,  49,  47,  5,
        227, 121, 247, 13,  235, 65,  63,  149, 115, 137, 7,   157, 123,
        81,  79,  37,  3,   153, 23,  45,  11,  97,  95,  181, 147, 169,
        39,  189, 155, 113, 111, 69,  35,  185, 55,  77,  43,  129, 127,
        213, 179, 201, 71,  221, 187, 145, 143, 101, 67,  217, 87,  109,
        75,  161, 159, 245, 211, 233, 103, 253, 219, 177, 175, 133, 99,
        249, 119, 141, 107, 193, 191, 21,  243, 9,   135, 29,  251, 209,
        207, 165, 131, 25,  151, 173, 139, 225, 223, 53,  19,  41,  167,
        61,  27,  241, 239, 197, 163, 57,  183, 205, 171, 1};
    uint8_t mask = masks[(n >> 1) & 127];
    i = (uint32_t)((mask * (s & 255)) & 255);
    j = i;
    s = (s + n * i) >> 8;
    i = (uint32_t)((mask * (s & 255)) & 255);
    j |= (uint64_t)i << 8;
    s = (s + n * i) >> 8;
    i = (uint32_t)((mask * (s & 255)) & 255);
    j |= (uint64_t)i << 16;
    s = (s + n * i) >> 8;
    i = (uint32_t)((mask * (s & 255)) & 255);
    j |= (uint64_t)i << 24;
    t = (uint32_t)((s + n * i) >> 8);
    i = (mask * (t & 255)) & 255;
    j |= (uint64_t)i << 32;
    t = (uint32_t)((t + n * i) >> 8);
    i = (mask * (t & 255)) & 255;
    j |= (uint64_t)i << 40;
    t = (uint32_t)((t + n * i) >> 8);
    i = (mask * (t & 255)) & 255;
    j |= (uint64_t)i << 48;
    t = (uint32_t)((t + n * i) >> 8);
    i = (mask * (t & 255)) & 255;
    j |= (uint64_t)i << 56;
    return j;
  };
  auto mont_mod_mul = [=](uint64_t a, uint64_t b, uint64_t npi) -> uint64_t {
    uint64_t ab_lo, ab_hi, mn_lo, mn_hi;
    uint64_t m, u;
    int carry;
    mul_u128(a, b, ab_lo, ab_hi);
    m = ab_lo * npi;
    mul_u128(m, n, mn_lo, mn_hi);
    carry = ab_lo + mn_lo < ab_lo ? 1 : 0;
    u = ab_hi + mn_hi + carry;
    return (u < ab_hi || u >= n) ? u - n : u;
  };
  if (n % 2 == 0) return n == 2;
  if (n % 3 == 0) return n == 3;
  if (n % 5 == 0) return n == 5;
  if (n % 7 == 0) return n == 7;
  if (n < 121) return n > 1;
  uint64_t d = n - 1;
  int s = __builtin_ctzll(d);
  d >>= s;
  uint64_t npi = mont_inv();
  uint64_t r = mont_u64_mod_n();
  uint64_t nr = n - r;
  for (uint32_t i = 0; i < v.size(); ++i) {
    uint64_t a = mul_mod_u64(v[i], r, n);
    uint64_t b = r, k = d;
    if (a == 0) continue;
    while (k > 0) {
      if (k & 1) b = mont_mod_mul(b, a, npi);
      a = mont_mod_mul(a, a, npi);
      k >>= 1;
    }
    if (b == r || b == nr) continue;
    int j;
    for (j = 1; j < s; ++j) {
      b = mont_mod_mul(b, b, npi);
      if (b == r) return false;
      if (b == nr) break;
    }
    if (j == s) return false;
  }
  return true;
}
bool isPrime(uint32_t n) {
  static const uint32_t bases[] = {
      0x3ce7, 0x07e2, 0x00a6, 0x1d05, 0x1f80, 0x3ead, 0x2907, 0x112f, 0x079d,
      0x050f, 0x0ad8, 0x0e24, 0x0230, 0x0c38, 0x145c, 0x0a61, 0x08fc, 0x07e5,
      0x122c, 0x05bf, 0x2478, 0x0fb2, 0x095e, 0x4fee, 0x2825, 0x1f5c, 0x08a5,
      0x184b, 0x026c, 0x0eb3, 0x12f4, 0x1394, 0x0c71, 0x0535, 0x1853, 0x14b2,
      0x0432, 0x0957, 0x13f9, 0x1b95, 0x0323, 0x04f5, 0x0f23, 0x01a6, 0x02ef,
      0x0244, 0x1279, 0x27ff, 0x02ea, 0x0b87, 0x022c, 0x089e, 0x0ec2, 0x01e1,
      0x05f2, 0x0d94, 0x01e1, 0x09b7, 0x0cc2, 0x1601, 0x01e8, 0x0d2d, 0x1929,
      0x0d10, 0x0011, 0x3b01, 0x05d2, 0x103a, 0x07f4, 0x075a, 0x0715, 0x01d3,
      0x0ceb, 0x36da, 0x18e3, 0x0292, 0x03ed, 0x0387, 0x02e1, 0x075f, 0x1d17,
      0x0760, 0x0b20, 0x06f8, 0x1d87, 0x0d48, 0x03b7, 0x3691, 0x10d0, 0x00b1,
      0x0029, 0x4da3, 0x0c26, 0x33a5, 0x2216, 0x023b, 0x1b83, 0x1b1f, 0x04af,
      0x0160, 0x1923, 0x00a5, 0x0491, 0x0cf3, 0x03d2, 0x00e9, 0x0bbb, 0x0a02,
      0x0bb2, 0x295b, 0x272e, 0x0949, 0x076e, 0x14ea, 0x115f, 0x0613, 0x0107,
      0x6993, 0x08eb, 0x0131, 0x029d, 0x0778, 0x0259, 0x182a, 0x01ad, 0x078a,
      0x3a19, 0x06f8, 0x067d, 0x020c, 0x0df9, 0x00ec, 0x0938, 0x1802, 0x0b22,
      0xd955, 0x06d9, 0x1052, 0x2112, 0x00de, 0x0a13, 0x0ab7, 0x07ef, 0x08b2,
      0x08e4, 0x0176, 0x0854, 0x032d, 0x5cec, 0x064a, 0x1146, 0x1427, 0x06bd,
      0x0e0d, 0x0d26, 0x3800, 0x0243, 0x00a5, 0x055f, 0x2722, 0x3148, 0x2658,
      0x055b, 0x0218, 0x074b, 0x2a70, 0x0359, 0x089e, 0x169c, 0x01b2, 0x1f95,
      0x44d2, 0x02d7, 0x0e37, 0x063b, 0x1350, 0x0851, 0x07ed, 0x2003, 0x2098,
      0x1858, 0x23df, 0x1fbe, 0x074e, 0x0ce0, 0x1d1f, 0x22f3, 0x61b9, 0x021d,
      0x4aab, 0x0170, 0x0236, 0x162a, 0x019b, 0x020a, 0x0403, 0x2017, 0x0802,
      0x1990, 0x2741, 0x0266, 0x0306, 0x091d, 0x0bbf, 0x8981, 0x1262, 0x0480,
      0x06f9, 0x0404, 0x0604, 0x0e9f, 0x01ed, 0x117a, 0x09d9, 0x68dd, 0x20a2,
      0x0360, 0x49e3, 0x1559, 0x098f, 0x002a, 0x119f, 0x067c, 0x00a6, 0x04e1,
      0x1873, 0x09f9, 0x0130, 0x0110, 0x1c76, 0x0049, 0x199a, 0x0383, 0x0b00,
      0x144d, 0x3412, 0x1b8e, 0x0b02, 0x0c7f, 0x032b, 0x039a, 0x015e, 0x1d5a,
      0x1164, 0x0d79, 0x0a67, 0x1264, 0x01a2, 0x0655, 0x0493, 0x0d8f, 0x0058,
      0x2c51, 0x019c, 0x0617, 0x00c2};
  if (n % 2 == 0) return n == 2;
  if (n % 3 == 0) return n == 3;
  if (n % 5 == 0) return n == 5;
  if (n % 7 == 0) return n == 7;
  if (n < 121) return n > 1;
  uint64_t h = n;
  h = ((h >> 16) ^ h) * 0x45d9f3b;
  h = ((h >> 16) ^ h) * 0x45d9f3b;
  h = ((h >> 16) ^ h) & 0xff;
  return isSprp(n, bases[h]);
}
bool isPrime(int32_t n) { return isPrime(static_cast<uint32_t>(n)); }
bool isPrime(uint64_t n) {
  static const std::vector<uint64_t> bases[] = {
      {4230279247111683200ULL, 14694767155120705706ULL,
       16641139526367750375ULL},
      {2ULL, 141889084524735ULL, 1199124725622454117ULL,
       11096072698276303650ULL},
      {2ULL, 4130806001517ULL, 149795463772692060ULL, 186635894390467037ULL,
       3967304179347715805ULL},
      {2ULL, 123635709730000ULL, 9233062284813009ULL, 43835965440333360ULL,
       761179012939631437ULL, 1263739024124850375ULL},
      {2ULL, 325ULL, 9375ULL, 28178ULL, 450775ULL, 9780504ULL, 1795265022ULL}};
  if (n < 7999252175582851ULL) {
    if (n < 350269456337ULL) {
      if (n < 4294967296ULL) {
        return isPrime(static_cast<uint32_t>(n));
      } else {
        return isSprp(n, bases[0]);
      }
    } else {
      if (n < 55245642489451ULL) {
        return isSprp(n, bases[1]);
      } else {
        return isSprp(n, bases[2]);
      }
    }
  } else {
    if (n < 585226005592931977ULL) {
      return isSprp(n, bases[3]);
    } else {
      return isSprp(n, bases[4]);
    }
  }
}
bool isPrime(int64_t n) { return isPrime(static_cast<uint64_t>(n)); }
}  // namespace algo
using namespace std;
using namespace algo;
namespace task {
int64_t k, a, b;
int main() {
  cin >> k >> a >> b;
  bool aa = a >= k, bb = b >= k;
  if ((a % k == 0 || bb) && (b % k == 0 || aa)) {
    cout << a / k + b / k << '\n';
  } else {
    cout << -1 << '\n';
  }
  return 0;
}
}  // namespace task
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.precision(11);
  cout.setf(ios::fixed);
  return task::main();
}
