#include <stdio.h>
#include <assert.h>

int faculteit(int n) {
    int i, res = 1;
    assert(n >= 0 && n <= 12);
    for (i = 1; i <= n; i = i + 1) {
        res = res * i;
    }
    return res;
} 

int main(void) {
    int n;
    for (n = 0; n <= 13; n = n + 1) {
        printf("%d! = %d\n", n, faculteit(n));
    }
    getchar();
    return 0;
}