#include <bits/stdc++.h>
#include <math.h>
using namespace std;
using ll = long long;
double R,X,Y;
vector<vector<ll>> v;
vector<vector<vector<int>>> seen;


int main() {
	cin >> R >> X >> Y;
	double d = sqrt(X * X + Y * Y);
	if (int(d)-d == 0 && int(d)%int(R) == 0) {
		cout << int(d) / int(R);
	}
	else if(int(d / R) != 0){
		cout << int(d / R) + 1;
	}
	else {
		cout << 2;
	}
}
#include<bits/stdc++.h>
using namespace std;
int main()
{
   int sum = 0;
   int n,k,m;
   cin>>n;
   cin>>k;
   cin>>m;
   int x;
   for(int i = 0;i<n-1;i++)
   {
        cin>>x;
        sum = sum+x;
   }
   if((m*n-sum)<=k)
   {
       if((m*n-sum)<0)
       {
           cout<<0;
       }
       else
       {
           cout<<m*n-sum;

       }
   }
   else
   {

       cout<<-1;
   }
}
