#include <stdio.h>

int factorial(int);

int main(void) {
    int input;
    scanf("%d", &input);

    int f = factorial(input);

    printf("%d", input);
    printf("! = ");
    printf("%d", f);
    putchar('\n');

    return 0;
}

int factorial(int n) {
    if (n == 0) {
        return 1;
    } else {
        return n * factorial(n - 1);
    }
}