#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    ll d;
    cin >> d;
    ll a = d / 25 * 2;
    if(d % 25 >= 13)a++;
    cout << d + a;
    int b = d % 25;
    b = b * 8;
    if(b >= 100)b -= 100;
    cout << '.';
    cout << setfill('0') << right << setw(2) << b;
    cout << endl;
    return 0;
}