#include<bits/stdc++.h>
using namespace std;

int main (){
  int64_t R,X,Y;
  cin >> R >> X >> Y ;
  
  int count =0;
  while((X*X+Y*Y)-(R*(count+1))*(R*(count+1))>0)count++;
  
  if(((X*X+Y*Y)-(R*(count+1))*(R*(count+1))==0))count++;
  else count++;
  
  if(count==1&&(X*X+Y*Y)-(R*(count))*(R*(count))!=0)count++;
  cout << count << endl;
  
}
#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vl;

#define mp make_pair
#define pb push_back
#define sz(x) ((int)((x).size()))
#define all(v) (v).begin(), (v).end()
#define endl "\n"
#define debug(x) cerr << __LINE__ << ' ' << #x << ':' << (x) << '\n'
#define files(name) ifstream fin(name".in"); ofstream fout(name".out");
template<typename T> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }

const int mod = 1e9 + 7;
const int mxN = 101;
const int inf = 1e9;


void solve() {
    ll r, x, y;
    cin >> r >> x >> y;
    ll d = x*x+y*y;
    if(d==r*r) {
        cout << 1 << endl;
        return;
    }
    for(ll i=2;; ++i) {
        if(r*r*i*i>=d) {
            cout << i << endl;
            return;
        }

    }
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
    
    //int tt;
    //cin >> tt;
    //while(tt--) {
        solve();
    //}
    return 0;
}
