#include<stdio.h>

int main(){
  
 unsigned long long int n,i,ans;
  ans=1;

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

    if (ans>=1000000000000000001)
    {
      printf("-1");
      return 0;
    }
  }
  
if(ans==0){
  printf("-1");
  return 0;
}  else{
   
 printf("%llu",ans);
}
 return 0; 
}