#include <bits/stdc++.h>   using namespace std;   mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());   long long Query(long long L, long long R) {     cout << L <<     << R << endl;     fflush(stdout);     string s;     cin >> s;     if (L == R && s ==  Yes ) exit(0);     return s ==  Yes ;   }   int32_t main() {     long long n, k;     cin >> n >> k;     long long L = 1, R = n;     while (true) {       if (R - L + 1 <= 4 * k + 7) {         long long M = L + rng() % (R - L + 1);         if (Query(M, M)) {           return 0;         } else {           L = max(1LL, L - k);           R = min(n, R + k);         }       } else {         long long M = L + ((R - L) >> 1);         if (Query(L, M)) {           L = max(1LL, L - k);           R = min(n, M + k);         } else {           L = max(1LL, M - k);           R = min(n, R + k);         }       }     }   }   