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

const long long MOD = 1e9+7;
const long long N = 1e5+10;
 
typedef long long ll;
typedef long double ld;

void test_case()
{ 
	ld r, x, y;
	cin >> r >> x >> y;
	ld dis = sqrt(x * x + y * y);
	ld res = dis/r;
	ll ans = ceil(res);
	if(ans == 1 && ceil(res) != floor(res))
		ans++;
	cout << ans << '\n';
}

int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL); 
    int tc = 1;
    // cin >> tc;
    while(tc--)
       test_case();
    return 0;
}
#include <vector>
#include <cstdlib>
#include <math.h> 
#include <algorithm>
#include <tuple>
#include <set>
#include <map>
#include <iostream>
#include <iomanip>
#include <limits>
using namespace std;
# define rep(i, n) for (long long i = 0; i < (long long)(n); i++)

int main() {
  long long r, x, y;
  cin >> r >> x >> y;
  long long answer = 0;

  long long d2 = (x * x) + (y * y);
  double d = sqrt(d2);
  
  if(fmod(d, r) == 0){
    answer = d / r;
  }else if(d < r * 2){
    answer = 2;
  }else{
    answer = ceil(d / r);
  }
  cout << answer << endl;
  return 0;
}