#include <bits/stdc++.h>
using namespace std;
#define ar array
#define ll long long

const int MAX_N = 2e5 + 1;
const int MOD = 1e9 + 7;
const int INF = 1e9;
const ll LINF = 1e18;
void solve()
{
    int v, t, s, d;
    cin >> v >> t >> s >> d;
    if (d >= v * t && d <= v * s)cout << "No" << endl;
    else cout << "Yes" << endl;
}

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

#ifndef ONLINE_JUDGE
    freopen("input1.txt", "r", stdin);
    freopen("output1.txt", "w", stdout);
#endif

    int t = 1;
    //cin >> t;
    while (t--)
        solve();
}

#include <bits/stdc++.h>

#define rep(i,n) for(int i=0; i<(n); i++)

using namespace std;
typedef long long ll;
typedef pair<int,int> P;

int main(){
    ll r,x,y;
    cin >> r >> x >> y;

    ll ans = 1;

    if(r*r == x*x+y*y) {
        cout << 1 << endl;
        return 0;
    }
    if(r*r > x*x+y*y) {
        cout << 2 << endl;
        return 0;
    }


    while((ans*r*ans*r) < x*x+y*y){ ans++;}

    
    cout << ans << endl;

}
