func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     int n;     cin >> n;     cout <<  0 0  << endl;     int l = 1, r = (int)1e9, mid = l + (r - l) / 2;     string s;     cin >> s;     int first;     if (s[0] ==  b ) {       first = 0;     } else {       first = 1;     }     for (int i = 1; i < n; i++) {       cout << mid <<     << mid << endl;       cin >> s;       if ((s[0] ==  w ) == first) {         l = mid + 1;       } else {         r = mid;       }       mid = l + (r - l) / 2;     }     if (l >= r && mid != (int)1e9) {       cout << mid - 1 <<     << mid <<     << mid <<     << mid - 1 << endl;     } else {       cout << mid <<     << 0 <<     << mid <<     << 1 << endl;     }     return 0;   }   