#include<bits/stdc++.h>
using namespace std;
long long int ans=0,n,m;
int main(){
	cin>>n>>m;
	for(long long int i=0;i<m;i++){
		n*=n;
		if(n>1000000000){
			cout<<-1;
			return 0;
		}
	}
	cout<<n;
}
/**************************************************************
	Problem: 2405
	User: zhengzihao
	Language: C++
	Result: Wrong Answer
****************************************************************/