#include<stdio.h>

int main(void){
  int n;
  scanf("%d",&n);

  long long a[n] , ans = 1;

  for(int i = 0;i < n;i ++){
  scanf("%lld",&a[i]);
  ans *= a[i];
  if(ans > 1000000000000000000){
    ans = -1;
    i += n;
  }
  }

  printf("%lld\n",ans);

  return 0;


}
