#include <bits/stdc++.h>

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define FOR(i,n,m) for(int i=(int)(n); i<=(int)(m); i++)
#define RFOR(i,n,m) for(int i=(int)(n); i>=(int)(m); i--)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define RITR(x,c) for(__typeof(c.rbegin()) x=c.rbegin();x!=c.rend();x++)
#define setp(n) fixed << setprecision(n)

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }

#define ll long long
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll,ll>
#define pi pair<int,int>

#define all(a) (a.begin()),(a.end())
#define rall(a) (a.rbegin()),(a.rend())
#define fi first
#define se second
#define pb push_back
#define ins insert

#define debug(a) cerr<<(a)<<endl
#define dbrep(a,n) rep(_i,n) cerr<<(a[_i])<<" "; cerr<<endl
#define dbrep2(a,n,m) rep(_i,n){rep(_j,m) cerr<<(a[_i][_j])<<" "; cerr<<endl;}

using namespace std;

template<class A, class B>
ostream &operator<<(ostream &os, const pair<A,B> &p){return os<<"("<<p.fi<<","<<p.se<<")";}
template<class A, class B>
istream &operator>>(istream &is, pair<A,B> &p){return is>>p.fi>>p.se;}

/* Some Libraries */

//-------------------------------------------------

ll my_sqrt(__int128_t n){
    __int128_t lo=0,hi=n;
    while(hi-lo>1){
        __int128_t c = (lo+hi)/2;
        (c*c<n)?(lo=c):(hi=c);
    }
    return hi;
}

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll R,X,Y; cin>>R>>X>>Y;
    if (X*X+Y*Y==R*R){
        cout<<"1\n";
        return 0;
    }
    if (X*X+Y*Y<R*R){
        cout<<"2\n";
        return 0;
    }
    ll ans = (my_sqrt(X*X+Y*Y)+R-1)/R;
    cout<<ans<<endl;
    return 0;
}

#include<iostream>
#include<cstdio>
#include<ctime>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<string>
#include<vector>
#include<iomanip>
#include<fstream>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<algorithm>
#include<sstream>
using namespace std;
#define sync std::ios::sync_with_stdio(false);std::cin.tie(0)
//string::npos
#define eps 1e-6
const double pi = 3.141592653589;
const int maxn = 2e5+10;
const int maxm = 100040;
//const int mod = 998244353;
const int inf = 0x3f3f3f3f;
typedef long long ll;



int main(){
    sync;

    double r, x, y;
    cin >> r >> x >> y;
    ll ans = ceil(sqrt(x*x+y*y)/r);
    //ll ans = ceil(sqrt(ceil(x*x+y*y/r/r);
    //cout << sqrt(x*x+y*y)/r*1.0 << endl;
    if(sqrt(x*x+y*y)/r<1) cout << 2 << endl;
    else cout << ans << endl;


	return 0;
}
