#include <bits/stdc++.h>
using namespace std;
double r, x, y;
int main()
{
	cin >> r >> x >> y;
	double d = hypot(x, y);
	cout << (d < r ? 2 : ceil(d / r)) << endl;
	return 0;
}
#include <bits/stdc++.h>

using namespace std;

typedef long long LL;

#define rep(i,n) for(LL i=0;i<(n);i++)

int main()
{
   LL r, x, y;
   LL output = 0;
   long double distance;

   cin >> r >> x >> y;

   distance = sqrt(x*x + y*y);

   if(r <= distance){
    output = distance/r;
    long double temp = distance/r;

    //cout << "temp:" << temp << endl;
    //cout << "dis:" << distance << endl;

    if(output != temp)
        output++;
   }
   else{
       output = 2;
   }


    cout << output << endl;

    return 0;
}