#include<stdio.h>

int main(){
  
 unsigned long long int n,b,i,ans;
  ans=1;
   
  (void) scanf("%llu",&n);
 
  for (i=0;i<n;i++)
  {
  (void) scanf("%llu",&b); 
    //printf("%llu\n",b);
    ans=ans*b;
    if (ans==0){
      printf("0");
      return 0;
    }
    if (ans>=1000000000000000001)
    {
      printf("-1");
      return 0;
    }
  }
   
 printf("%llu",ans);
   
 return 0; 
}