#include<stdio.h>

int main(void){

    int n;
    scanf("%d",&n);

    long long int a[n];
    long long int ans=1;
    for (int i=0;i<n;i++){
        scanf("%lld",&a[i]);
        ans=ans*a[i];
    }

    if (ans>1000000000000000000)
        printf("-1\n");
    else
        printf("%lld\n",ans);
    
    return 0;
}