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

typedef long long ll;

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

  ll dist = x*x + y*y;

  if(pow(dist, 0.5) < r) cout << 2 << endl;
  else cout << ceil(pow(dist, 0.5) / r) << endl;

  return 0;
}

#include <bits/stdc++.h>

using namespace std;

#define REP(i, a, b) for (ll i = a; i <= b; i++)
#define REP_REV(i, a, b) for (ll i = a; i >= b; i--)
#define debug(x) cerr << #x << " is " << x << endl;
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()
#define endl "\n"

#define pb push_back
#define rsz resize
#define f first
#define s second
#define mp make_pair

using ll = int64_t;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vc = vector<char>;
using ull = unsigned int64_t;
using pi = pair<int, int>;
using vl = vector<int64_t>;
using pl = pair<int64_t, int64_t>;
using vpl = vector<pair<int64_t, int64_t>>;
using msl = map<string, int64_t>;
using vvl = vector<vector<int64_t>>;

const ll MOD = 1e9 + 7;
const int INF = int(1e9);

bool isPrime(ll n) {
    if (n == 1) return false;
    if (n == 2) return true;
    for (ll i = 2; i * i <= n; i++) {
        if (n % i == 0) {
            return false;
        }
    }
    return true;
}

unsigned long long factorial(int n) {
    const unsigned int M = MOD;
    unsigned long long f = 1;
    for (int i = 1; i <= n; i++)
        f = (f * i) % M;
    return f;
}

ll expon(ll a, ll b, ll m = MOD) {
    ll res = 1;
    a %= m;
    while (b > 0) {
        if (b & 1)
            res = res * a % m;
        a = a * a % m;
        b >>= 1;
    }
    return res;
}

void solve() {
    double r, x, y;
    ll step = 0;
    cin >> r >> x >> y;
    double d = sqrt(x * x + y * y);
    if (d < r) {
        cout << 2;
        return;
    }
    while (1e-2 < d - r) {
        step++;
        d -= r;
        debug(d);
    }
    if (d < 1e-2) {
        cout << step;
        return;
    } else {
        step++;
        cout << step;
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
    int tt = clock();
#endif

    // freopen("paintbarn.in", "r", stdin);
    // freopen("paintbarn.out", "w", stdout);

    // ll t;
    // cin >> t;
    // while (t--)
    solve();

#ifdef _DEBUG
    cerr << "\nTIME = " << clock() - tt << endl;
    tt = clock();
#endif
    return 0;
}