func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2e5 + 100;   void ask(int r1, int c1, int r2, int c2) {     cout <<  ?   << r1 <<     << c1 <<     << r2 <<     << c2 <<   n ;     cout.flush();   }   bool ans() {     string ans;     cin >> ans;     return ans ==  YES ;   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     int n;     cin >> n;     int steps = 0;     int rx = 1, ry = 1;     string pre =   ;     while (steps < n - 1) {       ask(rx + 1, ry, n, n);       bool sol = ans();       if (sol) {         pre +=  D ;         rx++;       } else {         pre +=  R ;         ry++;       }       steps++;     }     string suf =   ;     steps = 0;     rx = n, ry = n;     while (steps < n - 1) {       ask(1, 1, rx, ry - 1);       bool sol = ans();       if (sol) {         suf +=  R ;         ry--;       } else {         suf +=  D ;         rx--;       }       steps++;     }     reverse(suf.begin(), suf.end());     cout <<  !   << (pre + suf) <<   n ;     cout.flush();   }   