#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ld  long double
#define fastIO ios_base::sync_with_stdio(false); cin.tie(0);
#define mod 1000000007

int main()
{
	double R,X,Y;
	cin>>R>>X>>Y;
	double K = sqrt(X*X + Y*Y);
	if(K == R)
		cout<<1<<endl;
	else if(K <= 2*R)
		cout<<2<<endl;
	else cout<<ceil(double(1.0 * K/R))<<endl;
}


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

typedef long long ll;
typedef long double ld;

bool ll_sqrt(ll x, ll& lower_bound, ll& upper_bound)
{
	constexpr ll ll_max = numeric_limits<ll>::max();
 
	bool first_boost = true;
 
	lower_bound = 0;
	upper_bound = x;
	while (upper_bound - lower_bound > 1)
	{
		if (first_boost)
		{
			ll guess = (ll)sqrt((double)x);
			lower_bound = max(guess - 1, (ll)0);
			upper_bound = lower_bound + 3;
			first_boost = false;
		}
 
		ll newval = (lower_bound + upper_bound) / 2;
		if ((newval != 0) && (newval > ll_max / newval))  // newval*newval becomes overflow
			upper_bound = newval;  // because overflow means newval is too big
		else
		{
			ll newval_sqr = newval * newval;
			if (newval_sqr < x)
				lower_bound = newval;
			else
				upper_bound = newval;
		}
	}
 
	if ((upper_bound != 0) && (upper_bound > ll_max / upper_bound))
	{
		if (lower_bound * lower_bound == x)
			upper_bound = lower_bound;
	}
	else
	{
		if (lower_bound * lower_bound == x)
			upper_bound = lower_bound;
		else if (upper_bound * upper_bound == x)
			lower_bound = upper_bound;
	}
	bool is_exact = (lower_bound == upper_bound);
	return is_exact;
}

ll ll_ceil(ll x, int digit);
ll ll_floor(ll x, int digit);


ll ll_floor(ll x, int digit)
{
	if (x < 0)
		return -ll_ceil(-x, digit);
 
	ll div = 1;
	while (digit != 0)
	{
		div *= 10;
		digit--;
	}
	ll modval = x % div;
	ll ans = x - modval;
	return ans;
}

ll ll_ceil(ll x, int digit)
{
	if (x < 0)
		return -ll_floor(-x, digit);
 
	ll div = 1;
	while (digit != 0)
	{
		div *= 10;
		digit--;
	}
	ll modval = x % div;
	ll ans = x - modval;
	if (modval != 0)
		ans += div;
	return ans;
}
int main() {
	ll R, X, Y;
	cin >> R >> X >> Y;

	R = R*R;

	ll ans = 0;

	ld dist = X*X + Y*Y;

	ld div = sqrt(dist / R);

	ans = ceil(sqrt(dist / R));

	if(div < 1){
		ans =2;
	}

	cout << ans << endl;

  return 0;
}