#include<iostream>
using namespace std;

int factorial(int inputNumber);


int main()
{
 int number,numFactorial;


 // Get input
 cout << "Input a number: ";
 cin >> number;


 // Compute factorial
 numFactorial=factorial(number);


 // Output result
 cout << number << "!=" << numFactorial << endl;


 return 0;
}


int factorial(int in_num)
{
 int output=1;

 for (int i=1;i<=in_num;i++)
 {
   output = output*i;
 }

 return output;
}