#include <stdio.h>

int factorial(int n)
{
	int result = 1;
	int i;
	for (i = n; i > 0; i--)
	{
		result = result * i;
	}

	return result;
}


int main()
{
	int number;
	int s;

	printf("enter a number:\n");
	scanf("%d", &number);

	s = factorial(number);
	printf("the result is %d\n", s);
}