#include <cstdio>
#include <algorithm>
#include <cmath>

using namespace std;

double r, x, y;
double p;

inline bool check()
{
	double c = p / r;
	if(int(c) * r == p) return 0;
	return 1;
}

int main()
{
	scanf("%lf%lf%lf", &r, &x, &y);
	p = 1.0 * sqrt(x * x + y * y);
	if (check()) printf("%d\n", int((p - r) / r) + 2);
	else printf("%d\n",int(p / r));
	return 0;
}
#include <bits/stdc++.h>
using namespace std;
#define int long long
using vec_int = vector<int>;
// using T = tuple<int,int,int>;
using P = pair<int,int>;
using ll = long long;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)

int charToInt(char c){
    char zero_num = '0';
    return (int)c - (int)zero_num;
}


signed main(){
    int R; cin>>R;
    int X, Y; cin>>X>>Y;

    int dist2 = X*X + Y*Y;
    if(dist2==R*R){
        cout<<1<<endl;
    }else if(dist2<R*R){
        cout<<2<<endl;
    }else{
        // int N2 = dist2/(R*R);
        for(int i=2;i<=1000000;i++){
            if(i*i*R*R>=dist2){
                cout<<i<<endl;
                return 0;
            }
        }

    }



    return 0;

}