#include <bits/stdc++.h>   using namespace std;   void winter_is_coming() {     std::ios_base::sync_with_stdio(0);     cin.tie(NULL);     cout.tie(NULL);   }   int main() {     void winter_is_coming();     long long a, b, dis, dis2, ans = 0;     cin >> a >> b;     dis = abs(a - b);     dis2 = dis / 2;     dis = dis - dis2;     ans = (dis * (dis + 1) / 2) + (dis2 * (dis2 + 1) / 2);     cout << ans << endl;     return 0;   }   