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

int main(void)
{
    long p;
    FILE *fi, *fo;

    fi=fopen("fact.in", "r");
    fo=fopen("fact.out", "w");

    while (fscanf(fi, "%ld", &p) != EOF)
    {
        ;
    }

    if(p<=1)
        fprintf(fo, "1\n");
    else
    {
        fprintf(fo, "%.0ld\n", (p-1)*5);
    }

    fclose(fi);
    fclose(fo);

    return 0;
}