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.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

public class Codeforces {

    private static final Scanner sc = new Scanner(System.in);
    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    private static final long MOD = (long) (1e9 + 7);

    public static int[] LPS(String p){
        int[] lps = new int[p.length()];

        int i=1;
        int j=0;
        while (i < p.length()){
            if (p.charAt(i) == p.charAt(j)){
                lps[i] = j+1;
                i++;
                j++;
            }
            else{
                if (j == 0){
                    lps[i] = 0;
                    i++;
                }
                else{
                    j = lps[j-1];
                }
            }
        }
        return lps;
    }

    public static void KMP(String text,String pattern){
        int[] lps = LPS(pattern);
        int i = 0;
        int j = 0;
        ArrayList<Integer> matches = new ArrayList<>();
        while (i < text.length()){
            if (text.charAt(i) == pattern.charAt(j)){
                i++;
                j++;
            }
            else{
                if (j != 0){
                    j = lps[j-1];
                }
                else {
                    i++;
                }
            }
            if (j == pattern.length()) {
                matches.add(i - j);
                j = lps[j-1];
            }
        }
        for (int x : matches){
            System.out.println("Match at : " + x);
        }
    }

    private static class SegmentTree{
        private long[] st;
        private int size;
        private int n;
        private long[] a;
        SegmentTree(long[] a,int n){
            this.size = 4*n;
            this.n = n;
            this.a = a;
            st = new long[size];
            //Arrays.fill(st,Integer.MIN_VALUE);
            buildSegmentTree(0,0,n-1);
            //printSegmentTree();
        }
        public long buildSegmentTree(int index,int l,int r){
            if (l == r){
                st[index] = a[l];
                return a[l];
            }
            int mid = (r+l) >> 1;
            return st[index] = buildSegmentTree(2*index+1,l,mid) + buildSegmentTree(2*index+2,mid+1,r);
        }
        public void printSegmentTree(){
            for (long x : st){
                System.out.print(x + " ");
            }
            System.out.println();
        }
        public long query(int ql,int qr){
            return getQuery(0,0,n-1,ql-1,qr-1);
        }
        private long getQuery(int index,int sl,int sr,int ql,int qr){
            //System.out.println("#" + index);
            if (qr < sl || ql > sr)
                return 0;
            if (ql <= sl && qr >= sr)
                return st[index];
            int mid = (sr + sl) >> 1;
            return getQuery(2*index+1,sl,mid,ql,qr) + getQuery(2*index+2,mid+1,sr,ql,qr);
        }
        public void update(int i,long newVal){
            //long diff = newVal - a[i];
            a[i] = newVal;
            updateSegmentTree(0,i,0,n-1,newVal);
        }
        private void updateSegmentTree(int index,int i,int sl,int sr,long diff){
            if (sl == sr){
                st[index] = diff;
                return;
            }
            int mid = (sl + sr) >> 1;
            if (i <= mid)
                updateSegmentTree(2*index+1,i,sl,mid,diff);
            else
                updateSegmentTree(2*index+2,i,mid+1,sr,diff);
            st[index] = st[2*index+1] + st[2*index+2];
        }
    }

    public static class Pair<T1,T2>{
        T1 first;
        T2 second;
        Pair(T1 a,T2 b){
            this.first = a;
            this.second = b;
        }

        @Override
        public String toString() {
            return "[" + first + ", " + second + "]";
        }
    }

    public static long GCD(long a,long b){
        if (b == 0)
            return a;
        return GCD(b,a%b);
    }

    static int highestPowerOf2(int n) {
        int p = (int)(Math.log(n) /
                Math.log(2));
        return (int)Math.pow(2, p);
    }

    public static int binSearch(long[] a,long x){
        int l = 0;
        int r = a.length - 1;
        while (l <= r){
            int mid = l + (r-l)/2;
            if (a[mid]==x)
                return 1;
            else if (a[mid] < x)
                l = mid+1;
            else
                r = mid-1;
        }
        return -1;
    }

    public static int upperBound(long[] arr,long key){
        int start=0;int end=arr.length-1;
        int idx=-1;
        int mid;
        while(start<=end){
            int i=(start+end)/2;
            if(arr[i]<key){
                start=i+1;
            }
            else if(arr[i]>key){
                end=i-1;
            }
            else{
                idx=i;
                start=i+1;
            }
        }

        return idx;    }

    public static int lowerBound(long[] arr,long key){
        int start=0;int end=arr.length-1;
        int idx=-1;
        int mid;
        while(start<=end){
            int i=(start+end)/2;
            if(arr[i]<key){
                start=i+1;
            }
            else if(arr[i]>key){
                end=i-1;
            }
            else{
                idx=i;
                end=i-1;
            }
        }
        return idx;
    }

    public static int searchInsert(long[] nums, long target) {
        int s=0,e=nums.length-1;
        int mid;
        if(target<nums[0]){
            return 0;
        }
        while(s<=e){
            mid=(s+e)/2;
            if(nums[mid]>target){
                e=mid-1;
            }
            else if(nums[mid]==target){
                return mid;
            }
            else{
                s=mid+1;
            }
        }
        return s;
    }

    static boolean isPrime(long n) {
        if (n <= 1)
            return false;
        if (n <= 3)
            return true;

        if (n % 2 == 0 || n % 3 == 0)
            return false;

        for (long i = 5; i <= Math.sqrt(n) + 1; i += 6)
            if (n % i == 0 || n % (i + 2) == 0)
                return false;

        return true;
    }

    public static long fastExpo(long a,long n,long mod){
        if (n == 0)
            return 1;
        else{
            long x = fastExpo(a,n/2,mod);
            if ((n&1) == 1){
                return (((a*x)%mod)*x)%mod;
            }
            else{
                return (((x%mod)*(x%mod))%mod)%mod;
            }
        }
    }

    public static long modInverse(long n,long p){
        return fastExpo(n,p-2,p);
    }

    public static long nCr(int n,int r,long[] fact,long mod){
        long val =  (((fact[n] * modInverse(fact[r],mod))%mod)*modInverse(fact[n-r],mod))%mod;
        return val;
    }

    public static void factorial(long[] fact,int n,long mod){
        for (int i=1;i<=n;i++){
            fact[i] = (fact[i-1] * i)%mod;
        }
    }

    public static int log2(long val){
        return (int) Math.floor(Math.log(val)/Math.log(2));
    }

    public static boolean isSubSequence(String s,String t){
        int i = 0;
        int j = 0;
        while (i < s.length() && j < t.length()){
            if (s.charAt(i) == t.charAt(j))
                j++;
            i++;
        }
        return j == t.length();
    }

    public static ArrayList<Long> getAllFactors(long x){
        ArrayList<Long> ans = new ArrayList<>();
        for (long i = 1; i <= Math.sqrt(x); i++) {
            if (x%i == 0){
                if (x/i == i){
                    ans.add(i);
                }
                else{
                    ans.add(i);
                    ans.add(x/i);
                }
            }
        }
        return ans;
    }

    public static boolean isPerfectSquare(long x){
        double val = Math.sqrt(x);
        return val*val == (double)x;
    }

    public static ArrayList<Integer> buildSieve(int n){
        boolean[] sieve = new boolean[n+1];
        Arrays.fill(sieve,true);
        sieve[0] = sieve[1] = false;
        for (int i = 2; i <= Math.sqrt(n+1) ; i++) {
            if (sieve[i]){
                for (int j = 2*i; j < n+1; j += i) {
                    sieve[j] = false;
                }
            }
        }
        ArrayList<Integer> primes = new ArrayList<>();
        for (int i = 0; i < sieve.length; i++) {
            if (sieve[i]){
                primes.add(i);
            }
        }
        return primes;
    }

    public static int getLowBit(int n){
        int x = 0;
        while ((n&1) != 1){
            x++;
            n >>= 1;
        }
        return 1 << x;
    }

    static boolean isDiophantinePossible(int a, int b, int c) {
        return (c % GCD(a, b) == 0);
    }

    public static boolean isPossible(long[][] M){
        int n = M.length;
        int m = M[0].length;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m - 1; j++) {
                if (M[i][j] >= M[i][j+1]){
                    return false;
                }
            }
        }
        for (int j = 0; j < m; j++) {
            for (int i = 0; i < n - 1; i++) {
                if (M[i][j] >= M[i+1][j]){
                    return false;
                }
            }
        }

        return true;
    }

    public static void solve() throws IOException {
        long k = sc.nextLong();
        long a = sc.nextLong();
        long b = sc.nextLong();
        if ((a >= k && b >= k) || (a > 0 && a%k == 0) || (b > 0 && b%k == 0)){
            System.out.println(a/k + b/k);
            return;
        }
        System.out.println(-1);
    }
    public static void main(String[] args) throws IOException {
        int t;
//        t = sc.nextInt();
        t = 1;
        while (t-- > 0){
            solve();
        }
        System.gc();
    }
}