#include <stdio.h>

FILE*citire=fopen("factorial.in","r");
FILE*scriere=fopen("factorial.out","w");
int main()
{
    int n,i,factorial=1;
    
    fscanf(citire,"%d", &n);
    
    if(factorial==0)
    {
     return 1;
    }
    for(i = 1; i <= n ;i++)
    {
        factorial=factorial*i;
    }
    fprintf(scrie,"%d", factorial);

    fclose(citire);
    fclose(scriere);
    return 0;
}