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.util.*;
  import java.io.*;
  public class B1594{
  	static FastScanner fs = null;
  	static long mod = (long)Math.pow(10,9)+(long)7;
  	public static void main(String[] args) {
  		fs = new FastScanner();
  		PrintWriter out = new PrintWriter(System.out);
  		int t = fs.nextInt();
  		while(t-->0){
  			int n = fs.nextInt();
  			int k = fs.nextInt();
  			int c = 0;
  			int count[] = new int[32];
  			while (k>0) {
  				int rem = k%2;
  				count[c++] = rem;
  				k>>=1;
  			}
  			long ans = 0;
  			for(int i=0;i<32;i++){
  				if(count[i]==1){
  					ans+=pow((long)n,i);
  					ans%=mod;
  				}
  			}
  		System.out.println(ans);
  	}
  	}
  	static long pow(long a,long b){
  		long ans = 1;
  		while(b>0){
  			if(b%2!=0)
  				ans*=a;
  			a*=a;
  			ans%=mod;
  			a%=mod;
  			b>>=1;
  		}
  		return ans%mod;
  	}
  	static void sort(int[] a) {
  		ArrayList<Integer> l=new ArrayList<>();
  		for (int i:a) l.add(i);
  		Collections.sort(l);
  		for (int i=0; i<a.length; i++) a[i]=l.get(i);
  	}
  	static class FastScanner {
  		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
  		StringTokenizer st=new StringTokenizer("");
  		String next() {
  			while (!st.hasMoreTokens())
  				try {
  					st=new StringTokenizer(br.readLine());
  				} catch (IOException e) {
  					e.printStackTrace();
  				}
  			return st.nextToken();
  		}
  		
  		int nextInt() {
  			return Integer.parseInt(next());
  		}
  		int[] readArray(int n) {
  			int[] a=new int[n];
  			for (int i=0; i<n; i++) a[i]=nextInt();
  			return a;
  		}
  		long nextLong() {
  			return Long.parseLong(next());
  		}
  	}
  }