#include <stdio.h>
int foo(int *,int);
int k=5;
int foo(int *x,int c)
{
	int res=1;
	c=c-1;
	if(c==0)
	return 1;
	
	*x=*x+1;
	res=foo(x,c);
	return res*(*x);
}

int main(void) {
    
	printf("\n%d",foo(&k,k));
	return 0;
}