
/**
 * Date: 04 Mar, 2018
 * Link :
 *
 * @author Prasad-Chaudhari
 * @email prasadc8897@gmail.com
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class New_File_1 {

    public static void main (String[] args) throws java.lang.Exception {
        FastIO2 in = new FastIO2();
        int a=in.ni();
        int b = in.ni();
        if(a>b){
            a^=b;
            b^=a;
            a^=b;
        }
        int diff = b-a;
        b-=a;
        System.out.println(diff/2*(diff/2+1)/2+(b-diff/2)*(b-diff/2+1)/2);
    }

    static class FastIO2 {

        private final BufferedReader br;
        private String s[];
        private int index;

        public FastIO2() throws IOException {
            br = new BufferedReader(new InputStreamReader(System.in));
            s = br.readLine().split(" ");
            index = 0;
        }

        public int ni() throws IOException {
            return Integer.parseInt(nextToken());
        }

        public double nd() throws IOException {
            return Double.parseDouble(nextToken());
        }

        public long nl() throws IOException {
            return Long.parseLong(nextToken());
        }

        public String next() throws IOException {
            return nextToken();
        }

        public String nli() throws IOException {
            return br.readLine();
        }

        public int[] gia(int n) throws IOException {
            int a[] = new int[n];
            for (int i = 0; i < n; i++) {
                a[i] = ni();
            }
            return a;
        }

        public int[] gia(int n, int start, int end) throws IOException {
            validate(n, start, end);
            int a[] = new int[n];
            for (int i = start; i < end; i++) {
                a[i] = ni();
            }
            return a;
        }

        public double[] gda(int n) throws IOException {
            double a[] = new double[n];
            for (int i = 0; i < n; i++) {
                a[i] = nd();
            }
            return a;
        }

        public double[] gda(int n, int start, int end) throws IOException {
            validate(n, start, end);
            double a[] = new double[n];
            for (int i = start; i < end; i++) {
                a[i] = nd();
            }
            return a;
        }

        public long[] gla(int n) throws IOException {
            long a[] = new long[n];
            for (int i = 0; i < n; i++) {
                a[i] = ni();
            }
            return a;
        }

        public long[] gla(int n, int start, int end) throws IOException {
            validate(n, start, end);
            long a[] = new long[n];
            for (int i = start; i < end; i++) {
                a[i] = ni();
            }
            return a;
        }

        private String nextToken() throws IndexOutOfBoundsException, IOException {
            if (index == s.length) {
                s = br.readLine().split(" ");
                index = 0;
            }
            return s[index++];
        }

        private void validate(int n, int start, int end) {
            if (start < 0 || end >= n) {
                throw new IllegalArgumentException();
            }
        }
    }
}

