func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 200001;   int n;   vector<pair<int, int> > a[N * 2];   vector<int> odd;   int used[N * 2], cur[N * 2];   char res[N];   void dfs(int u) {     while (cur[u] < a[u].size()) {       int v = a[u][cur[u]].first;       int pos = a[u][cur[u]].second;       if (used[pos]) {         cur[u]++;         continue;       }       if (pos <= n) {         if (u < N) {           res[pos] =  b ;         } else {           res[pos] =  r ;         }       }       used[pos] = 1;       dfs(v);       cur[u]++;     }   }   int main() {     ios_base::sync_with_stdio(0);     cin >> n;     for (int i = 1; i <= n; i++) {       int x, y;       cin >> x >> y;       a[x].push_back(make_pair(y + N, i));       a[y + N].push_back(make_pair(x, i));     }     for (int i = 1; i < N * 2; i++) {       if (a[i].size() % 2) {         odd.push_back(i);       }       used[i] = cur[i] = 0;     }     int cnt = n;     for (int i = 0; i < odd.size(); i += 2) {       cnt++;       a[odd[i]].push_back(make_pair(odd[i + 1], cnt));       a[odd[i + 1]].push_back(make_pair(odd[i], cnt));     }     for (int i = 1; i < N * 2; i++) {       dfs(i);     }     cout << (res + 1);     return 0;   }   