#include<stdio.h>

int main()
{
    freopen("fact.in", "r", stdin);
    freopen("fact.out", "w", stdout);

    int n, r;
    scanf("%d", &n);

    if (n == 0)
        r = 1;
    else {
        r = n * 5;
        if (r % 6)
            r = r / 6 + 1;
        else 
            r = r / 6;

        r *= 5;
    }

    printf("%d", r);

    return 0;
}