func_code_string: #include <bits/stdc++.h>   using namespace std;   template <class T>   inline void chkmin(T &a, T b) {     if (a > b) a = b;   }   template <class T>   inline void chkmax(T &a, T b) {     if (a < b) a = b;   }   int main() {     int N, x, M, y, d, len1, len2, len, r1, r2, r, i;     long long ans;     scanf( %d%d%d%d , &N, &x, &M, &y);     if (N < M) {       swap(x, y);       swap(N, M);     }     d = abs(x - y);     ans = N + M + 1 - max(min(M, N - d), 0);     for (i = 1; i <= N; i++) {       if (i <= d)         len1 = d - i + 1;       else         len1 = i - d;       len2 = 1;       r1 = d + i;       r2 = M;       len = max(len1, len2);       r = min(r1, r2);       ans += 2 * max(0, r - len + 1);       if (len1 <= r2) ans--;       if (r1 <= r2) ans -= 2;     }     printf( %I64d n , ans);     return 0;   }   