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

public class Main {

	public static void main (String[] args) throws IOException
	{	
		Scanner sc =  new  Scanner(System.in);
		int f1 = sc.nextInt();
		int f2 = sc.nextInt();
		int dis = Math.abs(f1 - f2);
		
		int m1 = dis / 2;
		int m2 = dis - m1;
		int tot = 0;
		for(int i = 1;i<=Math.max(m1, m2);i++)
		{
			if(i <= m1)
				tot += i;
			if(i <= m2)
				tot += i;
		}
		System.out.println(tot);
	}

	
	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public int[] nextIntArr(int n) throws IOException {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++)
				arr[i] = nextInt();
			return arr;
		}

		public long[] nextLongArr(int n) throws IOException {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++)
				arr[i] = nextLong();
			return arr;
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

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

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}
	}
}