#include <stdio.h>

int main(void)
{
  int n;
  scanf("%d", &n);
  long long int a[n];
  long long int ans;
  ans = 1;
  for(int i = 0; i != n; i++)
  {
    scanf("%lld", &a[i]);
    if(a[i] == 0)
    {
    a[0] = 0;
    }
  }
  for(int i = 0; i != n; i++)
  {
    ans = ans * a[i];
    if(ans > 1000000000000000000)
    {
      ans = -1;
      break;
    }
  }
  printf("%lld\n", ans);
  return 0;
}