#include<bits/stdc++.h>
using namespace std;
int main(){
	//freopen("pow.in","r",stdin);
	//freopen("pow.out","w",stdout);
	long long a,b,n;
	cin>>a>>b;
	for(int i=1;i<=b;i++){
		n*=a;
	}
	if(n>1000000000){
		cout<<-1;
	}else{
		cout<<n;
	}
	return 0;
	
}