#include<stdio.h>

int main() {

  unsigned long long loop, v, acc = 1;

  scanf("%lld", & loop);

  for (int i = 0; i < loop; ++i) {

    scanf("%lld", & v);
    if (v == 0) {
      printf("0\n");
      return 0;
    }

    if (acc != -1) {
      acc *= v;
      if (acc > 1000000000000000000) {
        acc = -1;
      }
    }

  }
  printf("%lld\n", acc);
  return 0;

}