func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long base = 233;   const long long ff = 4e5 + 1;   const long long mod = 1e9 + 7;   const long long inf = 1e17 + 1;   long long read() {     long long x;     scanf( %lld , &x);     return x;   }   inline long long Read() {     long long x = 0, f = 1;     char ch = getchar();     while (!isdigit(ch)) {       if (ch ==  - ) f = -1;       ch = getchar();     }     while (isdigit(ch)) {       x = (x << 3) + (x << 1) + ch -  0 ;       ch = getchar();     }     return x * f;   }   long long a, b, c, d;   long long my_max(long long x, long long y) { return (x > y) ? x : y; }   void init() {     long long ans = 0;     a = Read(), b = Read(), c = Read(), d = Read();     for (long long i = a; i <= b; ++i) {       long long st = my_max(min(i + b - c, d), 0LL);       long long ed = my_max(min(i + c - 1, d) - c + 1, 0LL);       long long q = max(ed - st + 1, 0LL);       ans += (st + ed) * q / 2;       if (i + c - 1 > d)         ans += my_max(min((i + c - 1) - d, c - b + 1), 0LL) * (d - c + 1);     }     cout << ans;   }   signed main() { init(); }   