import java.io.*;
import java.util.*;
 
 
public class Main{
static int mod = (int)(Math.pow(10, 9) + 7);
   public static void main(String[] args) {
      MyScanner sc = new MyScanner();
      out = new PrintWriter(new BufferedOutputStream(System.out));
      int r = sc.nextInt();
      int x1 = sc.nextInt();
      int y1 = sc.nextInt();
      int x2 = sc.nextInt();
      int y2 = sc.nextInt();
      
      int xdist = (int)Math.abs(x2 - x1);
      int ydist = (int)Math.abs(y2 - y1);
      int xturns = 0;
      int yturns = 0;
      
      // He can get anywhere in a 2r distance within 2 moves.
     while (xdist > 2*r){
       xdist -= r;
      xturns++; 
     }
     while (ydist > 2 * r){
       ydist -= r;
      yturns++;
     }
     //out.println(xturns + " " + yturns);
     int turns = 0;
     while (xturns > 0 && yturns > 0){
       turns++;
       xturns--;
       yturns--;
     }
     while (xturns > 1){
       xturns -= 2;
       turns++;
     }
     while (yturns > 1){
       yturns -=2;
       turns++;
     }
    if (xdist != 0 || ydist != 0){
      if (xdist == 0 && ydist == r){
        turns++;
      }
      else if (ydist == 0 && xdist == r){
        turns++;
      }
      else if (ydist == 0 && xdist == 2*r){
        turns++;
      }
      else if (ydist == 2*r && xdist == 0){
        turns++;
      }
      else turns+=2;
    }
      
      out.println(turns);
      
      out.close();
   }
   
   
   static long pow(long a, long N) {
	   if (N == 0) return 1;
	   else if (N == 1) return a;
	   else {
		   long R = pow(a,N/2);
		   if (N % 2 == 0) {
			   return R*R;
		   }
		   else {
			   return R*R*a;
		   }
	   }
   }
   
   static long powMod(long a, long N) {
	   if (N == 0) return 1;
	   else if (N == 1) return a % mod;
	   else {
		   long R = powMod(a,N/2) % mod;
		   R *= R % mod;
		   if (N % 2 == 0) {
			   R *= a % mod;
		   }
			   return R % mod;
	   }
   }
static void mergeSort(int[] A){ // low to hi sort, single array only
      int n = A.length;
      if (n < 2) return;
      int[] l = new int[n/2];
      int[] r = new int[n - n/2];
 
      for (int i = 0; i < n/2; i++){
        l[i] = A[i];
      }
 
      for (int j = n/2; j < n; j++){
        r[j-n/2] = A[j];
      }
 
      mergeSort(l);
      mergeSort(r);
      merge(l, r, A);
    }
 
    static void merge(int[] l, int[] r, int[] a){
      int i = 0, j = 0, k = 0;
      while (i < l.length && j < r.length && k < a.length){
        if (l[i] < r[j]){
          a[k] = l[i];
          i++;
        }
        else{
          a[k] = r[j];
          j++;
        }
        k++;
      }
      while (i < l.length){
        a[k] = l[i];
        i++;
        k++;
      }
 
      while (j < r.length){
        a[k] = r[j];
        j++;
        k++;
      }
    }

   

   //-----------PrintWriter for faster output---------------------------------
   public static PrintWriter out;
      
   //-----------MyScanner class for faster input----------
   public static class MyScanner {
      BufferedReader br;
      StringTokenizer st;
 
      public MyScanner() {
         br = new BufferedReader(new InputStreamReader(System.in));
      }
 
      String next() {
          while (st == null || !st.hasMoreElements()) {
              try {
                  st = new StringTokenizer(br.readLine());
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
          return st.nextToken();
      }
 
      int nextInt() {
          return Integer.parseInt(next());
      }
 
      long nextLong() {
          return Long.parseLong(next());
      }
 
      double nextDouble() {
          return Double.parseDouble(next());
      }
 
      String nextLine(){
          String str = "";
	  try {
	     str = br.readLine();
	  } catch (IOException e) {
	     e.printStackTrace();
	  }
	  return str;
      }

   }
   //--------------------------------------------------------
}





