#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b;
	long long s=1;
	cin>>a>>b;
	if(a>=10&&b>=10){
		cout<<-1;
	}else{
		for(int i=1;i<=b;i++){
				s*=a;
			}
			if(s>1000000000){
				cout<<-1;
			}else{
				cout<<s;	
			}	
	}
	return 0;
}

/**************************************************************
	Problem: 2405
	User: zzz
	Language: C++
	Result: Accepted
	Time:988 ms
	Memory:2072 kb
****************************************************************/