giaithua_tuananh

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <conio.h>

long int giaithua(int x) {
    long int P = 1;
    for (int i = 1 ; i<=x; i++) {
        P = P*i;
    }
    return(P);
}


int main() {
    int n;
    long int a;
    scanf("%d", &n);
    a = giaithua(n);
    printf("%ld", a);

    return(0);
}