func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t, n;     cin >> t;     while (t--) {       int n, m, aux1, aux2;       int q;       cin >> q;       string ans =   ;       vector<pair<int, int> > v;       for (int i = 0; i < q; i++) {         cin >> n >> m;         v.push_back(make_pair(n, m));       }       sort(v.begin(), v.end());       bool f1 = true;       bool f2 = true;       int contr = 0;       for (auto i = v.begin(); i != v.end(); i++) {         if (f1) {           aux1 = i->first;           aux2 = i->second;           contr = aux2;           f1 = false;           for (int k = 0; k < aux1; k++) ans +=  R ;         } else {           if (aux2 > (i->second)) {             cout <<  NO  << endl;             f2 = false;             break;           }           if (aux1 != i->first) {             for (int k = 0; k < contr; k++) ans +=  U ;             contr = 0;           }           contr += (i->second - aux2);           for (int k = aux1; k < i->first; k++) ans +=  R ;           aux1 = i->first;           aux2 = i->second;         }       }       if (f2) {         for (int k = 0; k < contr; k++) ans +=  U ;         cout <<  YES  << endl;         cout << ans << endl;       }     }     return 0;   }   