description: Theofanis really likes sequences of positive integers, thus his teacher (Yeltsa Kcir) gave him a problem about a sequence that consists of only special numbers.
  
  Let's call a positive number special if it can be written as a sum of different non-negative powers of n. For example, for n = 4 number 17 is special, because it can be written as 4^0 + 4^2 = 1 + 16 = 17, but 9 is not.
  
  Theofanis asks you to help him find the k-th special number if they are sorted in increasing order. Since this number may be too large, output it modulo 10^9+7.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10^4) — the number of test cases.
  
  The first and only line of each test case contains two integers n and k (2 ≤ n ≤ 10^9; 1 ≤ k ≤ 10^9).
  
  Output
  
  For each test case, print one integer — the k-th special number in increasing order modulo 10^9+7.
  
  Example
  
  Input
  
  
  3
  3 4
  2 12
  105 564
  
  
  Output
  
  
  9
  12
  3595374
  
  Note
  
  For n = 3 the sequence is [1,3,4,9...]
solution: import java.io.*;
  import java.util.*;
  
  public class Main {
  
      static int MOD = 1000000007;
  
      static class FastReader {
          BufferedReader br;
          StringTokenizer st;
  
          public FastReader() throws IOException {
              br = new BufferedReader(new InputStreamReader(System.in));
  
          }
  
          String next() throws NumberFormatException, IOException, NullPointerException {
              while (st == null || !st.hasMoreElements()) {
                  st = new StringTokenizer(br.readLine());
              }
              return st.nextToken();
          }
  
          int nextInt() throws NumberFormatException, IOException, NullPointerException {
              return Integer.parseInt(next());
          }
  
          long nextLong() throws NumberFormatException, IOException, NullPointerException {
              return Long.parseLong(next());
          }
  
          double nextDouble() throws NumberFormatException, IOException, NullPointerException {
              return Double.parseDouble(next());
          }
  
          String nextLine() {
              String str = "";
              try {
                  str = br.readLine();
              } catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
      }
  
      static boolean ToCheckPowerofX(long n, long x) {
  
          while (n > 0) {
  
              long rem = n % x;
  
              if (rem >= 2) {
                  return false;
              }
  
              n = n / x;
          }
          return true;
      }
  
      static long pow(long a, long b) {
          if (b == 0) {
              return 1;
          }
          if (b == 1) {
              return a;
          }
          long ans = pow(a, b / 2) % MOD;
          ans = (ans * ans) % MOD;
          if (b % 2 == 1) {
  
              return (a * ans) % MOD;
          }
          return ans;
      }
  
      public static void main(String[] args) throws IOException {
          BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
          FastReader sc = new FastReader();
  
          long t = sc.nextLong();
  
          // long t = 1;
  
          while (t-- > 0) {
              long n = sc.nextLong();
              long k = sc.nextLong();
  
              long ans = 0;
  
              int i = 0;
  
              while (k > 0) {
                  if (k % 2 == 1) {
                      long temp = (long) pow(n, i);
                      // System.out.println(temp);
                      ans += temp;
                  }
  
                  i++;
                  k /= 2;
              }
  
              log.write(ans % MOD + "\n");
          }
  
          log.flush();
      }
  
  }
  