func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2e5 + 10;   int n, l[N], r[N], cnt[4 * N], one[4 * N];   vector<int> g;   map<int, int> mp;   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cin >> n;     for (int i = 1; i <= n; ++i) {       cin >> l[i] >> r[i];       g.push_back(l[i] - 1);       g.push_back(l[i]);       g.push_back(r[i]);       g.push_back(r[i] + 1);     }     sort(g.begin(), g.end());     for (int i = 0, cnt = 0; i < g.size(); ++i) {       if (!i || g[i] != g[i - 1]) cnt++;       mp[g[i]] = cnt;     }     for (int i = 1; i <= n; ++i) {       cnt[mp[l[i]]]++;       cnt[mp[r[i] + 1]]--;     }     for (int i = 1; i <= 4 * n; ++i) {       cnt[i] += cnt[i - 1];       if (cnt[i] == 1) {         one[i] = 1;       }       one[i] += one[i - 1];     }     for (int i = 1; i <= n; ++i) {       if (one[mp[r[i]]] == one[mp[l[i] - 1]]) {         cout << i <<   n ;         return 0;       }     }     cout <<  -1 n ;   }   