func_code_string: #include <bits/stdc++.h>   using namespace std;   long long K, statc;   int qc;   bool query(long long l, long long r) {     qc++;     assert(qc <= 4499);     cout << l <<     << r <<   n ;     fflush(stdout);     string ans;     cin >> ans;     if (l == r && ans[0] ==  Y ) {       exit(0);     }     if (ans[0] ==  B ) {       exit(0);     }     return ans[0] ==  Y ;   }   long long randrange(long long l, long long r) {     long long mod = r - l + 1;     return l + rand() % mod;   }   long long extl(long long x) { return max(1LL, x - K); }   long long extr(long long x) { return min(statc, x + K); }   int main() {     srand(time(NULL));     ios::sync_with_stdio(false);     cin >> statc >> K;     long long l = 1, r = statc;     while (true) {       long long w = r - l + 1;       if (w <= 7 * K) {         long long guess = randrange(l, r);         query(guess, guess);       } else {         long long mid = (l + r) / 2;         if (query(l, mid)) {           r = mid;         } else {           l = mid + 1;         }       }       l = extl(l);       r = extr(r);     }   }   