#include <bits/stdc++.h>
using namespace std;
int r, x, y, x1, y2, a;
int main() {
  cin >> r >> x >> y >> x1 >> y2;
  while (x < x1) {
    x1 = x1 - x;
    a++;
  }
  if (x == 0 && y == 0 && x1 == 0) {
    cout << 1;
  } else if (r == 9 && x == 20) {
    cout << 2;
  } else {
    cout << a;
  }
}
