func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     vector<int> l(n), r(n);     for (int i = 0; i < n; i++) {       cin >> l[i] >> r[i];     }     int a = -1, b = -1;     bool ok = true;     for (int i = 0; i < n; i++) {       for (int j = 0; j < n; j++) {         if (!((l[i] <= l[j] && r[i] <= r[j]) || (l[j] <= l[i] && r[j] <= l[i]))) {           if (a == -1) {             a = i;             b = j;           } else {             if (a == i && j == b)               continue;             else if (a == j && b == i)               continue;             else if (i == a && j != b) {               b = -1;             } else if (i == b && j != a) {               a = i;               b = -1;             } else if (j == a && i != b) {               b = -1;             } else if (j == b && i != a) {               a = j;               b = -1;             } else {               ok = false;             }           }         }       }     }     if (!ok)       cout <<  0 n ;     else if (a == -1 && b == -1) {       cout << n <<   n ;       for (int i = 0; i < n; i++) {         cout << i + 1 <<    ;       }       cout <<   n ;     } else if (b == -1) {       cout <<  1 n  << a + 1 <<   n ;     } else {       if (a > b) swap(a, b);       cout <<  2 n  << a + 1 <<     << b + 1 <<   n ;     }   }   