#include <stdio.h>
 
long long power (int b, int p); 

int main() {
    int n;
    scanf("%d",&n);
    long long arr[n],product=1;
    for ( int i=0 ; i<n ; ++i ) {
        scanf("%lld",&arr[i]);
        product *= arr[i];
        if ( product > power(10,18))
            break;
    }
    if ( product <= power(10,18)) {
        printf("%lld",product);
    }
    else
        printf("-1");
}

long long power (int b, int p) {
    long long power=1;
    for ( int i=0 ; i<p ; ++i) {
        power *= b;
    }
    return power;
}