#include<stdio.h>

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