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: //package cn.weixiaochen.contest_1594.B;
  
  import java.io.*;
  import java.math.BigInteger;
  import java.util.StringTokenizer;
  
  public class B extends Solution {
  
      public static final int mod = 1000000000 + 7;
  
      @Override
      public void solve(Input in, Output out) throws IOException {
          int T = in.nextInt();
          while (T-- > 0) {
              int n = in.nextInt(), k = in.nextInt();
  
              BigInteger ans = new BigInteger("0");
              int i = 0;
              while (k > 0) {
                  if ((k & 1)== 1) {
                      ans = ans.add(new BigInteger(String.valueOf(n)).pow(i));
                  }
                  i++;
                  k >>= 1;
              }
  
              out.println(ans.mod(new BigInteger(String.valueOf(mod))));
          }
      }
  }
  
  abstract class Solution {
      abstract void solve(Input input, Output output) throws IOException;
  
      public static void main(String[] args) throws IOException {
          Input in = new Input();
          Output out = new Output();
          new B().solve(in, out);
          out.close();
      }
  }
  
  class Input {
      private final BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
      private StringTokenizer tokenizer = new StringTokenizer("");
  
      private String innerNextLine() {
          try {
              return reader.readLine();
          } catch (IOException ex) {
              return null;
          }
      }
  
      public boolean hasNext() {
          while (!tokenizer.hasMoreTokens()) {
              String nextLine = innerNextLine();
              if (nextLine == null) {
                  return false;
              }
              tokenizer = new StringTokenizer(nextLine);
          }
          return true;
      }
  
      public String nextLine() {
          tokenizer = new StringTokenizer("");
          return innerNextLine();
      }
  
      public String next() {
          return hasNext() ? tokenizer.nextToken() : null;
      }
  
      public int nextInt() {
          return Integer.parseInt(next());
      }
  
      public Long nextLong() {
          return Long.parseLong(next());
      }
  
      public Double nextDouble() {
          return Double.parseDouble(next());
      }
  }
  
  
  class Output implements Closeable {
      private final BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
  
      public void print(Object object) throws IOException {
          writer.write(object.toString());
      }
  
      public void println(Object object) throws IOException {
          writer.write(object.toString());
          writer.write(System.lineSeparator());
      }
  
      @Override
      public void close() throws IOException {
          writer.close();
      }
  }