#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3")
#include <bits/stdc++.h>

#define el '\n'
#define F first
#define S second

typedef long long ll;
typedef long double ld;
typedef __int128 bigInt;

using namespace std;

const int N = 4e5 + 5, INF = 1e9 + 5, mod = 1e9 + 7, LOG = 21, SQ = 500;



void doWork() {
    int n;
    cin >> n;
    int full = n / 4, rem = n % 4;
    cout << full << '.';
    if (rem == 0) {
        cout << "00";
    }
    else if (rem == 1) {
        cout << "25";
    }
    else if (rem == 2) {
        cout << "50";
    }
    else {
        cout << "75";
    }
}

int main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    int tests = 1;
//    cin >> tests;
    for (int i = 1; i <= tests; i++) {
        doWork();
    }
}