#include <bits/stdc++.h>
//#include <atcoder/modint>

using namespace std;
//using namespace atcoder;
using ll = long long;
//using mint = modint998244353;

int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);

    ll N;
    cin >> N;

    ll l=0, r=N, c;
    while(r-l>1){
        c = (l+r)/2;
        if (N-c*500<100) r=c;
        else l=c;
    }
    cout << r << endl;

    return 0;
}