#include <bits/stdc++.h>   using namespace std;   void use_cio() {     ios_base::sync_with_stdio(0);     cin.tie(0);   }   template <typename... Args>   void dbg(Args... args) {     ((cout << args <<    ), ...);     cout << endl;   }   int n;   int ask(int r1, int c1, int r2, int c2) {     string ans;     dbg( ? , r1, c1, r2, c2);     cout.flush();     cin >> ans;     return (ans ==  YES );   }   int main() {     cin >> n;     string l, r;     int sx = 1, sy = 1;     while (sx + sy < n + 1) {       if (sy + 1 <= n && ask(sx, sy + 1, n, n)) {         sy++;         l +=  R ;       } else {         sx++;         l +=  D ;       }     }     int ex = n, ey = n;     while (ex + ey > n + 1) {       if (ex && ask(1, 1, ex - 1, ey)) {         ex--;         r +=  D ;       } else {         ey--;         r +=  R ;       }     }     reverse(r.begin(), r.end());     dbg( ! , l + r);   }   