#include "bits/stdc++.h" using namespace std; using ll = long long; int INF = numeric_limits<int>::max() / 2; ll LINF = numeric_limits<ll>::max() / 2; int MOD = 1e9 + 7; int main(){ cin.tie(0); ios::sync_with_stdio(false); ll n; cin >> n; cout << n * 15 / 10 << endl; }