UVA 10323

import java.math.*;
import java.util.*;

public class Main {
 public static void main(String args[]){

  Scanner sc = new Scanner(System.in);
  BigInteger a , r;
  int n;

  while(sc.hasNextInt()){

   n = sc.nextInt();

   if(n < 0){
    n = Math.abs(n);
    if(n%2 == 0)
     System.out.println("Underflow!");
    else System.out.println("Overflow!");
   }

   else if(n < 8)
    System.out.println("Underflow!");

   else if(n >= 14)
    System.out.println("Overflow!");

   else{
    a = new BigInteger("1");
    r = new BigInteger("1");
    int i = 1;

    while(i <= n){
     r = r.multiply(a);
     a = a.add(new BigInteger("1"));
     i++;
    }

    System.out.println(r);
   }
  }

 }
}