func_code_string: #include <bits/stdc++.h>   using namespace std;   long long ans = 0;   int n, m, x, y;   int main() {     while (scanf( %d%d%d%d , &n, &x, &m, &y) == 4) {       if (x > y) {         n ^= m ^= n ^= m;         x ^= y ^= x ^= y;       }       ans = n + 1;       int l, r;       for (int i = 1; i <= m; ++i) {         l = y - i;         r = y + i;         if (l <= x - n || l >= x + n)           ++ans;         else {           r = min(r - 1, n + x);           if (l >= x)             ans += ((r - l) << 1);           else             ans += ((r - x - (x - l)) << 1) + 1;         }       }       cout << ans << endl;     }     return 0;   }   