#include <bits/stdc++.h>
using namespace std;
int main() {
  int r, x, y, x1, y1;
  cin >> r >> x >> y >> x1 >> y1;
  float d = sqrt((x1 - x) * (x1 - x) + (y1 - y) * (y1 - y));
  int p = d / (2 * r);
  if ((p - 1) * r >= d)
    cout << p - 1 << "glob";
  else if (p * r >= d) {
    cout << p;
  } else {
    cout << p + 1;
  }
  return 0;
}
