#include<iostream>
#include<cmath>
using namespace std;
int n,a,b; 
int main(){
	cin>>a>>b;
	n=a;
	for(int i= 1;i<b;i++){
		n=n*a;
	}
	if(n>1000000000){
		cout<<-1;
	}else{
		cout<<n;
	}
	return 0;
}