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.*; import java.math.*;
  public class Main{
  	//見なくていいよ　ここから------------------------------------------
  	static class InputIterator{
  		ArrayList<String> inputLine = new ArrayList<>(buf);
  		int index = 0; int max; String read;
  		InputIterator(){
  			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  			try{
  				while((read = br.readLine()) != null){
  					inputLine.addAll(Arrays.asList(read.split(" ")));
  				}
  			}catch(IOException e){}
  			max = inputLine.size();
  		}
  		boolean hasNext(){return (index < max);}
  		String next(){
  			if(hasNext()){
  				return inputLine.get(index++);
  			}else{
  				throw new IndexOutOfBoundsException("There is no more input");
  			}
  		}
  	}
  	//入力バッファサイズのつもり。入力点数（スペース区切りでの要素数）が100万を超える場合はバッファサイズを100万にすること
  	static int buf = 1024;
  	static HashMap<Integer, String> CONVSTR = new HashMap<>();
  	static InputIterator ii = new InputIterator();//This class cannot be used in reactive problem.
  	static PrintWriter out = new PrintWriter(System.out);
  	static void flush(){out.flush();}
  	static void myout(Object t){out.println(t);}
  	static void myerr(Object t){System.err.print("debug:");System.err.println(t);}
  	static String next(){return ii.next();}
  	static boolean hasNext(){return ii.hasNext();}
  	static int nextInt(){return Integer.parseInt(next());}
  	static long nextLong(){return Long.parseLong(next());}
  	static double nextDouble(){return Double.parseDouble(next());}
  	static ArrayList<String> nextCharArray(){return myconv(next(), 0);}
  	static ArrayList<String> nextStrArray(int size){
  		ArrayList<String> ret = new ArrayList<>(size);
  		for(int i = 0; i < size; i++){
  			ret.add(next());
  		}
  		return ret;
  	}
  	static ArrayList<Integer> nextIntArray(int size){
  		ArrayList<Integer> ret = new ArrayList<>(size);
  		for(int i = 0; i < size; i++){
  			ret.add(Integer.parseInt(next()));
  		}
  		return ret;
  	}
  	static ArrayList<Long> nextLongArray(int size){
  		ArrayList<Long> ret = new ArrayList<>(size);
  		for(int i = 0; i < size; i++){
  			ret.add(Long.parseLong(next()));
  		}
  		return ret;
  	}
  	@SuppressWarnings("unchecked")
  	static String myconv(Object list, int no){//only join
  		StringBuilder sb = new StringBuilder("");
  		String joinString = CONVSTR.get(no);
  		if(list instanceof String[]){
  			return String.join(joinString, (String[])list);
  		}else if(list instanceof long[]){
  			long[] tmp = (long[])list;
  			if(tmp.length == 0){
  				return "";
  			}
  			sb.append(String.valueOf(tmp[0]));
  			for(int i = 1; i < tmp.length; i++){
  				sb.append(joinString).append(String.valueOf(tmp[i]));
  			}
  			return sb.toString();
  		}else if(list instanceof int[]){
  			int[] tmp = (int[])list;
  			if(tmp.length == 0){
  				return "";
  			}
  			sb.append(String.valueOf(tmp[0]));
  			for(int i = 1; i < tmp.length; i++){
  				sb.append(joinString).append(String.valueOf(tmp[i]));
  			}
  			return sb.toString();
  		}else if(list instanceof ArrayList){
  			ArrayList tmp = (ArrayList)list;
  			if(tmp.size() == 0){
  				return "";
  			}
  			sb.append(tmp.get(0));
  			for(int i = 1; i < tmp.size(); i++){
  				sb.append(joinString).append(tmp.get(i));
  			}
  			return sb.toString();
  		}else{
  			throw new ClassCastException("Don't join");
  		}
  	}
  	static ArrayList<String> myconv(String str, int no){//only split
  		String splitString = CONVSTR.get(no);
  		return new ArrayList<String>(Arrays.asList(str.split(splitString)));
  	}
  	static ArrayList<String> myconv(String str, String no){
  		return new ArrayList<String>(Arrays.asList(str.split(no)));
  	}
  	public static void main(String[] args){
  		CONVSTR.put(8, " "); CONVSTR.put(9, "\n"); CONVSTR.put(0, "");
  		solve();flush();
  	}
  	//見なくていいよ　ここまで------------------------------------------
  	//このコードをコンパイルするときは、「-encoding UTF-8」を指定すること
  	static void solve(){//ここがメイン関数
  		int t = nextInt();
  		int mod = 1000000007;
  		while(hasNext()){
  			int N = nextInt();
  			int K = nextInt();
  			long output = 0;
  			int count = 0;
  			while(K > 0){
  				if(K % 2 == 1){
  					output += mypow(N, count, mod);
  				}
  				count++;
  				K /= 2;
  				output %= mod;
  			}
  			myout(output);
  		}
  	}
  	//メソッド追加エリア　ここから
  
  static long mypow(long x, long n) {return mypow(x, n, -1);}
  static long mypow(long x, long n, long m) {
      long ans = 1;
      while (n > 0) {
          if ((n & 1) == 1){
              ans *= x;
              if(m != -1){
                  ans %= m;
              }
          }
          x *= x;
          if(m != -1){
              x %= m;
          }
          n >>= 1;
      }
      return ans;
  }
  
  	//メソッド追加エリア　ここまで
  }
  