func_code_string: #include <bits/stdc++.h>   using namespace std;   inline long long read() {     long long s = 0, w = 1;     register char ch = getchar();     while (ch <  0  || ch >  9 ) {       if (ch ==  - ) w = -1;       ch = getchar();     }     while (ch >=  0  && ch <=  9 )       s = (s << 3) + (s << 1) + (ch ^ 48), ch = getchar();     return s * w;   }   void print(long long x) {     if (x < 0) x = -x, putchar( - );     if (x > 9) print(x / 10);     putchar(x % 10 +  0 );   }   long long n, c, x, y, res = 1, now = 1;   signed main() {     n = read(), x = read(), y = read(), c = read();     if (c == 1) {       puts( 0 );       return 0;     }     for (; c > res; now++) {       long long L = min(now, y - 1);       if (L == now) res--;       res += max(0ll, L - max(now - x + 1, 1ll) + 1) +              max(0ll, L - max(x + now - n, 1ll) + 1);       long long R = min(now, n - y);       if (R == now) res--;       res += max(0ll, R - max(now - x + 1, 0ll) + 1) +              max(0ll, R - max(x + now - n, 0ll) + 1);     }     printf( %lld n , --now);     return 0;   }   