func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 200000;   pair<int, bool> p[N * 2];   pair<int, int> t[N];   int main() {     int n;     scanf( %d , &n);     int l, r;     for (int i = 0; i < n; ++i) {       scanf( %d%d , &l, &r);       t[i] = make_pair(l, r);       p[i * 2].first = l;       p[i * 2].second = false;       p[i * 2 + 1].first = r + 1;       p[i * 2 + 1].second = true;     }     sort(p, p + n * 2);     int current = 0;     vector<int> v;     for (int i = 0; i < n * 2; ++i) {       if (!p[i].second)         ++current;       else         --current;       if ((i == n * 2 - 1 || p[i + 1].first != p[i].first) && current == 1)         v.push_back(p[i].first);     }     for (int i = 0; i < n; ++i) {       int it = lower_bound(v.begin(), v.end(), t[i].first) - v.begin();       if (it == v.size() || (v[it] > t[i].second)) {         printf( %d n , i + 1);         return 0;       }     }     printf( -1 n );     return 0;   }   