#include <stdio.h>

int main() {
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
    
    int n;
    scanf("%d",&n);
    if (n == 0) {
        printf("1\n");
        return 0;
    }    

    int exp = 0;
    int cur;
    for (cur = 5; exp < n; cur += 5) {
        int tmp = cur;
        while (tmp % 5 == 0) {
            ++exp;
            tmp /= 5;
        }    
    }   
    printf("%d\n",cur-5);
    return 0;
}