Bitwise tuple june long challenge

help
1

/* package codechef; // don’t place package name! */

import java.util.;
import java.lang.;
import java.io.*;

/* Name of the class has to be “Main” only if the class is public. */
class Codechef
{
public static void main (String[] args) throws java.lang.Exception
{
// your code goes here
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
long T = Long.parseLong(reader.readLine());
while(T!=0){
long N,M;
String[] input =new String[2];
input = reader.readLine().split(" ");

	        N = Long.parseLong(input[0]);
	        M = Long.parseLong(input[1]);
	        
	        long a = power(2,N);
	        long b = power(a-1,M);
	        
	        System.out.println(b%1000000007);
	   T--;
	}
        }
	catch(Exception e){
	    e.printStackTrace();
	}
}

static long power(long N, long M){
    long res = 1;
            while (M > 0) {
                if ((M & 1)!=0)
                     res = res * N;
                M = M>>1;
                N = N*N;
	        }
	  return res;     
}

}

WHY GETTING “WA” in this answer .