Problem: You are given n intervals in form [l; r] on a number line.

You are also given m queries in form [x; y]. What is the minimal number of intervals you have to take so that every point (not necessarily integer) from x to y is covered by at least one of them? 

If you can't choose intervals so that every point from x to y is covered, then print -1 for that query.

Input

The first line contains two integers n and m (1 ≤ n, m ≤ 2 ⋅ 10^5) — the number of intervals and the number of queries, respectively.

Each of the next n lines contains two integer numbers l_i and r_i (0 ≤ l_i < r_i ≤ 5 ⋅ 10^5) — the given intervals.

Each of the next m lines contains two integer numbers x_i and y_i (0 ≤ x_i < y_i ≤ 5 ⋅ 10^5) — the queries.

Output

Print m integer numbers. The i-th number should be the answer to the i-th query: either the minimal number of intervals you have to take so that every point (not necessarily integer) from x_i to y_i is covered by at least one of them or -1 if you can't choose intervals so that every point from x_i to y_i is covered.

Examples

Input


2 3
1 3
2 4
1 3
1 4
3 4


Output


1
2
1


Input


3 4
1 3
1 3
4 5
1 2
1 3
1 4
1 5


Output


1
1
-1
-1

Note

In the first example there are three queries:

  1. query [1; 3] can be covered by interval [1; 3]; 
  2. query [1; 4] can be covered by intervals [1; 3] and [2; 4]. There is no way to cover [1; 4] by a single interval; 
  3. query [3; 4] can be covered by interval [2; 4]. It doesn't matter that the other points are covered besides the given query. 



In the second example there are four queries:

  1. query [1; 2] can be covered by interval [1; 3]. Note that you can choose any of the two given intervals [1; 3]; 
  2. query [1; 3] can be covered by interval [1; 3]; 
  3. query [1; 4] can't be covered by any set of intervals; 
  4. query [1; 5] can't be covered by any set of intervals. Note that intervals [1; 3] and [4; 5] together don't cover [1; 5] because even non-integer points should be covered. Here 3.5, for example, isn't covered. 

Solution (in JAVA):

Solution:
// Don't place your source in a package
import javax.swing.*;
import java.lang.reflect.Array;
import java.text.DecimalFormat;
import java.util.*;
import java.lang.*;
import java.io.*;
import java.math.*;
import java.util.stream.Stream;


// Please name your class Main
public class Main {
    static FastScanner fs=new FastScanner();
    static class FastScanner {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st=new StringTokenizer("");
        public String next() {
            while (!st.hasMoreElements())
                try {
                    st=new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }
        int Int() {
            return Integer.parseInt(next());
        }

        long Long() {
            return Long.parseLong(next());
        }

        String Str(){
            return next();
        }
    }


    public static void main (String[] args) throws java.lang.Exception {
        PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));

        int T=1;
        for(int t=0;t<T;t++){
            int n=Int();
            int m=Int();

            int A[][]=new int[n][2];
            int q[][]=new int[m][2];

            for(int i=0;i<n;i++){
                A[i][0]=Int();
                A[i][1]=Int();
            }

            for(int i=0;i<m;i++){
                q[i][0]=Int();
                q[i][1]=Int();
            }

            Solution sol=new Solution(out);
            sol.solution(A,q);
        }
        out.close();

    }


    public static int Int(){
        return fs.Int();
    }
    public static long Long(){
        return fs.Long();
    }
    public static String Str(){
        return fs.Str();
    }

}






class Solution{
    PrintWriter out;
    public Solution(PrintWriter out){
        this.out=out;
    }





    public void solution(int pairs[][],int q[][]){
        int f[][]=new int[500010][21];
        for(int i=0;i<f.length;i++){
            Arrays.fill(f[i],-1);
        }

        for(int p[]:pairs){
            int l=p[0],r=p[1];
            f[l][0]=Math.max(f[l][0],r);
        }


        for(int i=1;i<f.length;i++){
            if(i<=f[i-1][0]) {//is cover
                f[i][0] = Math.max(f[i][0], f[i - 1][0]);
            }
        }


       /* for(int i=0;i<6;i++){
            System.out.print(f[i][0]+" ");
        }
        System.out.println();*/


        for(int j=1;j<f[0].length;j++){
            for(int i=0;i<f.length;i++){
                if(f[i][j-1]==-1)continue;
                f[i][j]=f[f[i][j-1]][j-1];
            }
        }


        for(int p[]:q){
            int mn=Integer.MAX_VALUE;
            int l=p[0],r=p[1];
            int sum=0;
            for(int i=f[0].length-1;i>=0;i--){
                if(f[l][i]==-1)continue;
                if(f[l][i]>=r){
                    mn=Math.min(mn,sum+(1<<i));
                }
                else{
                    sum+=(1<<i);
                    l=f[l][i];
                }
            }


            if(mn!=Integer.MAX_VALUE){
                out.println(mn);
            }
            else{
                out.println(-1);
            }
        }


    }






}


/*
2 1
1 3
2 4
1 4

*/


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