func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e6 + 40;   int v[N], x[N], ct, al[N], col[N], n, lu[N], lv[N];   int read() {     int sum = 0, fg = 1;     char c = getchar();     while (c <  0  || c >  9 ) {       if (c ==  - ) fg = -1;       c = getchar();     }     while (c >=  0  && c <=  9 ) {       sum = sum * 10 + c -  0 ;       c = getchar();     }     return sum * fg;   }   inline void add(int u, int V) {     v[++ct] = V;     x[ct] = al[u];     al[u] = ct;   }   inline void dfs(int u, int tw) {     col[u] = tw;     for (int i = al[u]; i; i = x[i])       if (col[v[i]] == -1) dfs(v[i], tw ^ 1);   }   int main() {     n = read();     for (int i = 1; i <= n; i++) col[i] = -1;     for (register int i = 1, x, y; i <= n; i++) {       x = read();       y = read();       if (lu[x]) {         add(lu[x], i);         add(i, lu[x]);         lu[x] = 0;       } else         lu[x] = i;       if (lv[y]) {         add(lv[y], i);         add(i, lv[y]);         lv[y] = 0;       } else         lv[y] = i;     }     for (register int i = 1; i <= n; i++)       if (col[i] == -1) dfs(i, 0);     for (register int i = 1; i <= n; i++)       if (col[i] == 0)         cout <<  b ;       else         cout <<  r ;     return 0;   }   