#include <bits/stdc++.h>
#define INFILE "fact.in"
#define OUTFILE "fact.out"
using namespace std;
typedef long long ll;
ifstream in(INFILE);
ofstream out(OUTFILE);
ll generare(ll p){
    if(p==0)
        return 1;
    ll num=5;
    ll f=1;
    ll s=1;
    while(s<p){
        f++;
        num = f*5;
        s++;
        if(f%5==0)
            s++;
    }
    return num;
}
int main()
{
    ll p;
    in>>p;
    out<<generare(p);
    return 0;
}