

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */



public class Main {

	static int k;
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader();
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
        	
        	int a=in.nextInt();
        	int b=in.nextInt();
        	
        	int x=Math.abs(a-b);
        	if(x%2==0) {
        		x=x/2;
        		int ans=x*(x+1)/2;
        		System.out.println(ans*2);
        		
        	}
        	else {
        		x=x/2;
        		
        		int ans=(x*(x+1))/2;
        		
        		System.out.println(2*ans+x+1);
        	}
        	
        	
        	
        	
            
      
        	
        
        	
        }	
        
    }
    
    static int comb(int n , int r)
	{
		if( r== 0 || n == r)
			return 1;
		else
			return comb(n-1,r)+comb(n-1,r-1);
	}
    

    static class InputReader
    {
        BufferedReader br;
        StringTokenizer st;

        public InputReader()
        {
            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;
        }
    
    }
   
   
   
}