#include <cstdio>
using namespace std;
#define ll long long

ll r, x, y;

ll read() {
	ll X = 0, F = 1; char C = getchar();
	while(C < '0' || C > '9') {if(C == '-')F=-1; C = getchar();}
	while(C >= '0' && C <= '9') {X = X*10+C-'0'; C = getchar();}
	return X * F;
}

int main() {
	r = read(); x = read(); y = read();
	ll dis = x * x + y * y;
	r = r * r;
	for(ll i = 0;; ++i)
		if(i * i * r >= dis) {
			printf("%lld\n", i == 1 ? (i * i * r == dis ? 1 : 2) : i);
			break;
		}
	return 0;
}
#include <bits/stdc++.h>
using namespace std;

int main() {
  long long R, X, Y, ans;
  double k;
  cin >> R >> X >> Y;
  k = sqrt(X * X + Y * Y);
  
  ans = ceil(k / R);
  if(k < R) ans++;
  
  cout << ans << endl;
}