func_code_string: #include <bits/stdc++.h>   #pragma GCC optimize( Ofast )   using namespace std;   long long max(long long a, long long b) {     if (a > b) {       return a;     } else {       return b;     }   }   long long min(long long a, long long b) {     if (a < b) {       return a;     } else {       return b;     }   }   long long rand_int(long long l, long long r) {     static mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());     return uniform_int_distribution<long long>(l, r)(gen);   }   long long power(long long b, long long e) {     if (e == 0) return 1;     if (e % 2)       return ((b * power((b) * (b), (e - 1) / 2)));     else       return power((b) * (b), e / 2);   }   long long modpower(long long b, long long e, long long q) {     long long MOD = q;     if (e == 0) return 1;     if (e % 2)       return ((b % MOD) * modpower((b % MOD) * (b % MOD), (e - 1) / 2, q)) % MOD;     else       return modpower((b % MOD) * (b % MOD), e / 2, q) % MOD;   }   void dpv(vector<long long> v) {     for (long long i = 0; i < v.size(); i++) {       cout << v[i] <<    ;     }     cout << endl;   }   void dpv(vector<pair<long long, long long> > v) {     for (long long i = 0; i < v.size(); i++) {       cout << v[i].first <<     << v[i].second << endl;     }   }   void dpv(set<long long> v) {     for (auto i : v) {       cout << i <<    ;     }     cout << endl;   }   bool check(long long l, long long r) {     assert(l <= r);     cout << l <<     << r << endl;     string s;     cin >> s;     if (s ==  Bad ) {       exit(0);     }     if (s ==  Yes ) {       if (l == r) exit(0);       return true;     }     return false;   }   void oblivious() {     srand(time(0));     long long n, K;     cin >> n >> K;     long long L = 1, R = n;     while (true) {       if (R - L + 1 > 70) {         long long M = (L + R) / 2;         if (check(L, M))           R = M;         else           L = M + 1;       } else {         long long p = rand() % (R - L + 1) + L;         check(p, p);       }       L = max(1LL, L - K);       R = min(n, R + K);     }   }   signed main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     long long t = 1;     while (t--) {       oblivious();     }     return 0;   }   