#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, c = 0, s = 0, k = 0, p = 0, j, r, q, t, x = 0, y = 0, a, b = 0, f,
            d = 0, i;
  cin >> n >> m;
  if (n > m) {
    j = n / m;
  } else {
    r = m / n;
  }
  if (n > m) {
    q = n - j;
    while (n != q) {
      n--;
      c++;
      s = s + c;
    }
    a = q - m;
    for (i = 1; i <= a; i++) {
      b = b + i;
    }
    cout << s + b;
  } else if (m > n) {
    t = m - r;
    while (m != t) {
      m--;
      k++;
      p = p + k;
    }
    f = t - n;
    for (i = 1; i <= f; i++) {
      d = d + i;
    }
    cout << d + p;
  }
}
