#include <bits/stdc++.h>   using namespace std;   unsigned long long min(unsigned long long x, unsigned long long y) {     if (x < y) return x;     return y;   }   unsigned long long max(unsigned long long x, unsigned long long y) {     if (x < y) return y;     return x;   }   long long min(long long x, long long y) {     if (x < y) return x;     return y;   }   long long max(long long x, long long y) {     if (x < y) return y;     return x;   }   double min(double x, double y) {     if (x < y) return x;     return y;   }   double max(double x, double y) {     if (x < y) return y;     return x;   }   unsigned long long gcd(unsigned long long x, unsigned long long y) {     if (!x) return y;     if (!y) return x;     if (x > y) swap(x, y);     return gcd(x, y % x);   }   unsigned long long inv(unsigned long long a, unsigned long long c) {     if (a == 1) {       return 1;     }     return ((c - (c / a)) * inv(c % a, c)) % c;   }   int n, l[300005] = {0}, r[300005] = {0}, idx[300005] = {0};   int comp(int a, int b) {     if (l[a] == l[b]) return r[a] > r[b];     return l[a] < l[b];   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     cin >> n;     for (int i = 0; i < n; ++i) {       cin >> l[i] >> r[i];       idx[i] = i;     }     sort(idx, idx + n, comp);     int minr = r[idx[n - 1]], j = n - 1;     for (int i = n - 2; i >= 0; --i) {       if (minr <= r[idx[i]]) {         cout << (idx[j] + 1) <<     << (idx[i] + 1) <<   n ;         return 0;       }       if (r[idx[i]] < minr) {         j = i;         minr = r[idx[i]];       }     }     cout <<  -1 -1 n ;     return 0;   }   