#include<iostream>
#include<vector>
#include<algorithm>
#include<set>
#include<map>
#include<queue>
#include<cmath>
#include<iomanip>
#include<cstring>
#include<complex>
#include<cstdio>
#define initdp(a,b) for(int i=0;i<=a;i++)for(int j=0;j<=b;j++)dp[i][j]=-1;
#define fi first
#define se second
#define pb push_back
#define pii pair<int,int>
#define ppi pair<pii,int>
#define pip pair<int,pii>
#define ll long long
#define pll pair<ll,ll>
#define rep(i,n) for(int i=0;i<n;i++)
#define repd(i,n) for(int i=n-1;i>=0;i--)
#define inf 1000000001
#define inf1 1000000000000000001
#define mod 1000000007
#define pie 3.14159265358979323846
#define N 100005
#define mid(l,r) l+(r-l)/2
#define removeduplicates(vec) vec.erase( unique( vec.begin(), vec.end() ), vec.end() )
#define memset1(v) memset(v,-1,sizeof(v))
#define memset0(v) memset(v,0,sizeof(v))
using namespace std;
int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
int ddx[8]={1,1,0,-1,-1,-1,0,1},ddy[8]={0,1,1,1,0,-1,-1,-1};
void mad(ll &a,ll b){a=(a+b)%mod;if(a<0)a+=mod;}
ll gcd(ll a,ll b){ if(!a)return b;return gcd(b%a,a);}

void solve(){
	long double r,x,y;
	cin>>r>>x>>y;
	long double d=sqrt(x*x+y*y);
	if(d==r)cout<<1;
	else if(d<=r+r)cout<<2;
	else cout<<ceil(d/r);
}
int32_t main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	int t=1;
	//cin>>t;
	while(t--){
		solve();
	}
}
#include <bits/stdc++.h>
using namespace std;
//const long nPrime = 1000000007;
//const long nPrime = 998244353;
int main() {
    long r,x,y;
    cin >> r >> x >> y;
    if(x*x+y*y == r*r){
        cout << "1" << endl;
        return 0;
    }
    long nSq = (x*x+y*y+r*r-1) / (r*r);
    long nAns = long(sqrt(double(nSq)));
    if(nAns * nAns < nSq){
        nAns++;
    }
    nAns = max(nAns , 2L);
    cout << nAns << endl;
    return 0;
}