#include <bits/stdc++.h>
using namespace std;
const int MX = 1e5 + 10, MD = 1e9 + 7;
long long n, m, a[MX], tmp, x, y, sec, res1, res2;
vector<pair<long long, pair<long long, long long>>> ans;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> n;
  if (n == 1) {
    cout << -1 << " " << -1;
    return 0;
  }
  for (int i = 1; i <= n; i++) {
    cin >> x >> y;
    ans.push_back({x, {1e9 - y, i}});
  }
  sort(ans.begin(), ans.end());
  for (int i = 0; i < n; i++) {
    ans[i].second.first = 1e9 - ans[i].second.first;
  }
  tmp = ans[0].second.first;
  sec = ans[0].second.second;
  res1 = -1;
  res2 = -1;
  for (int i = 1; i < n; i++) {
    if (ans[i].second.first <= tmp) {
      res1 = ans[i].second.second;
      res2 = sec;
    }
    if (ans[i].second.first > tmp) {
      tmp = ans[i].second.first;
      sec = ans[i].second.second;
    }
  }
  cout << res1 << " " << res2 << endl;
}
