func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, k, ans;   bool chk_odd(long long lim) {     long long get = 0, bas = 1, val = lim * 2 + 1;     for (int i = 1; i <= 60; ++i, bas *= 2) {       long long start = val * bas;       if (start > n) break;       get += min(bas, n - start + 1);     }     return get >= k;   }   void Solve_Odd() {     long long l = 0, r = (n & 1) ? n / 2 : n / 2 - 1;     while (l < r) {       long long mid = (l + r) / 2;       if (chk_odd(mid + 1))         l = mid + 1;       else         r = mid;     }     if (l == r && chk_odd(l)) ans = max(ans, 2 * l + 1);   }   bool chk_even(long long lim) {     long long get = 0, bas = 1, val = lim * 2;     for (int i = 1; i <= 60; ++i, bas *= 2) {       long long start = val * bas;       if (start > n) break;       get += min(bas * 2, n - start + 1);     }     return get >= k;   }   void Solve_Even() {     long long l = 1, r = n / 2;     while (l < r) {       long long mid = (l + r) / 2;       if (chk_even(mid + 1))         l = mid + 1;       else         r = mid;     }     if (l == r && chk_even(l)) ans = max(ans, 2 * l);   }   int main() {     scanf( %lld%lld , &n, &k);     Solve_Odd(), Solve_Even();     printf( %lld , ans);     return 0;   }   