import java.io.*;
import java.util.*;
import java.math.*;
public class test
{
	static class Reader 
    { 
        final private int BUFFER_SIZE = 1 << 16; 
        private DataInputStream din; 
        private byte[] buffer; 
        private int bufferPointer, bytesRead; 
  
        public Reader() 
        { 
            din = new DataInputStream(System.in); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        } 
  
        public Reader(String file_name) throws IOException 
        { 
            din = new DataInputStream(new FileInputStream(file_name)); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        } 
  
        public String readLine() throws IOException 
        { 
            byte[] buf = new byte[10000000]; // line length 
            int cnt = 0, c; 
            while ((c = read()) != -1) 
            { 
                if (c == '\n') 
                    break; 
                buf[cnt++] = (byte) c; 
            } 
            return new String(buf, 0, cnt); 
        }
	
	public String readWord() throws IOException 
        { 
            byte[] buf = new byte[10000000]; // word length 
            int cnt = 0, c; 
            while ((c = read()) != -1) 
            { 
                if (c == '\n' || c==' ') 
                    break; 
                buf[cnt++] = (byte) c; 
            } 
            return new String(buf, 0, cnt); 
        } 
		
        public int nextInt() throws IOException 
        { 
            int ret = 0; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
            do
            { 
                ret = ret * 10 + c - '0'; 
            }  while ((c = read()) >= '0' && c <= '9'); 
  
            if (neg) 
                return -ret; 
            return ret; 
        } 
  
        public long nextLong() throws IOException 
        { 
            long ret = 0; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
            do { 
                ret = ret * 10 + c - '0'; 
            } 
            while ((c = read()) >= '0' && c <= '9'); 
            if (neg) 
                return -ret; 
            return ret; 
        } 
  
        public double nextDouble() throws IOException 
        { 
            double ret = 0, div = 1; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
  
            do { 
                ret = ret * 10 + c - '0'; 
            } 
            while ((c = read()) >= '0' && c <= '9'); 
  
            if (c == '.') 
            { 
                while ((c = read()) >= '0' && c <= '9') 
                { 
                    ret += (c - '0') / (div *= 10); 
                } 
            } 
  
            if (neg) 
                return -ret; 
            return ret; 
        } 
  
        private void fillBuffer() throws IOException 
        { 
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
            if (bytesRead == -1) 
                buffer[0] = -1; 
        } 
  
        private byte read() throws IOException 
        { 
            if (bufferPointer == bytesRead) 
                fillBuffer(); 
            return buffer[bufferPointer++]; 
        } 
  
        public void close() throws IOException 
        { 
            if (din == null) 
                return; 
            din.close(); 
        } 
    }
	static class obj
	{
		int ind;
		int val;
		public obj(int a,int b)
		{
			ind=a;
			val=b;
		}
	}
	static class objcomparator implements Comparator<obj>
	{
		public int compare(obj s1, obj s2)
		{
			if(s1.val<s2.val)
				return 1;
			else if(s1.val>s2.val)
				return -1;
				return 1;
		}
	}
	static boolean isPrime(long n) 
    	{  
        	if (n <= 1) return false; 
       		if (n <= 3) return true; 
      
	        if (n % 2 == 0 || n % 3 == 0) return false; 
      
     		   for (int i = 5; i * i <= n; i = i + 6) 
     		       if (n % i == 0 || n % (i + 2) == 0) 
     			       return false; 
      
        	return true; 
    	}
	 
	public static void main (String[] args) throws IOException
	{
		Scanner sc=new Scanner(System.in);
		int r=sc.nextInt();
		int xi=sc.nextInt();
		int yi=sc.nextInt();
		int xf=sc.nextInt();
		int yf=sc.nextInt();
		int max=Math.max(Math.abs(xi-xf),Math.abs(yi-yf));
		if(max/r!=0)
			System.out.println((max/r)-1);
		else
			System.out.println("0");
	}
}
	
	
