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