#include <stdio.h>


int f1(int x)
{
 if(x <= 1) return 1;
 return x * f1(x - 1);
}

int f2s(int x, int y)
{
 if(x <= 1) return y;
 return f2s(x - 1, x * y);
}
int f2(int x)
{
 f2s(x, 1);
}



int main(void)
{
 printf("%d\n", f1(10));
 printf("%d\n", f2(10));
}