蒟蒻60分求助

#include<bits/stdc++.h>
using namespace std;
int main(){
	long long a , b;
	cin >> a >> b;
	double sum;
	sum = pow(a , b);
	double m = 1000000000;
	if(sum < m){
		cout << sum;
	}
	else{
		cout << -1;
	}
	return 0;
}