#include <bits/stdc++.h>
using namespace std;
const long double PI = 3.141592653589793;
const long double E = 2.71828182845904523;
const long long LLINF = 4000000009000000099;
const long long INF = 1009000099;
const long long MOD7 = 1000000007;
const long long MOD9 = 1000000009;
template <class A, class B, class C>
struct triple {
  A first;
  B second;
  C third;
  triple(A, B, C);
  triple();
};
template <class A, class B, class C>
triple<A, B, C>::triple(A a, B b, C c) {
  first = a;
  second = b;
  third = c;
}
template <class A, class B, class C>
triple<A, B, C>::triple() {}
template <class A, class B, class C>
triple<A, B, C> make_triple(A a, B b, C c) {
  triple<A, B, C> t(a, b, c);
  return t;
}
template <class A, class B, class C>
bool operator<(triple<A, B, C> a, triple<A, B, C> b) {
  if (a.first != b.first) return a.first < b.first;
  if (a.second != b.second) return a.second < b.second;
  if (a.third != b.third) return a.third < b.third;
}
template <class T>
T inline sqr(T a) {
  return a * a;
}
long long bpow(long long a, long long d, long long mod) {
  if (d == 0) return 1;
  long long t = bpow(a, d / 2, mod);
  t = (t * t) % mod;
  if (d & 1) t = (t * a) % mod;
  return t;
}
long long bpow(long long a, long long d) {
  if (d == 0) return 1;
  long long t = bpow(a, d / 2);
  t = (t * t);
  if (d & 1) t = (t * a);
  return t;
}
long long gcd(long long a, long long b) {
  while (a && b)
    if (a > b)
      a %= b;
    else
      b %= a;
  return a + b;
}
long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
long long C(long long n, long long k) {
  long long res = 1;
  for (int i = 1; i <= k; ++i) res = res * (n - k + i) / i;
  return res;
}
long long C(long long n, long long k, long long mod) {
  long long u = 1, d = 1;
  for (int i = 2; i <= n; ++i) u = (u * i) % mod;
  int x = max(k, n - k), z = min(k, n - k);
  for (int i = 2; i <= x; ++i) {
    d = (d * i) % mod;
    if (i <= z) d = (d * i) % mod;
  }
  d = bpow(d, mod - 2, mod);
  long long res = (u * d) % mod;
  return res;
}
vector<pair<long long, long long>> vc;
bool cmp(triple<long long, long long, int> a,
         triple<long long, long long, int> b) {
  if (a.first != b.first) return a.first < b.first;
  if (a.third == 1 && b.third == 1) {
    int c1 = vc[a.second].second;
    int c2 = vc[b.second].second;
    if (c1 != c2)
      return c1 > c2;
    else
      return a.second < b.second;
  }
  if (a.third != 1 && b.third != 1) {
    int c1 = vc[a.second].first;
    int c2 = vc[b.second].first;
    if (c1 != c2)
      return c1 > c2;
    else
      return a.second > b.second;
  }
  if (a.third == 1 && b.third != 1)
    return 1;
  else
    return 0;
}
void solve() {
  long long n;
  cin >> n;
  vc.resize(n);
  for (int i = 0; i < n; ++i) cin >> vc[i].first >> vc[i].second;
  vector<triple<long long, long long, int>> ev;
  for (int i = 0; i < n; ++i) {
    ev.push_back(make_triple(vc[i].first, (long long)i, 1));
    ev.push_back(make_triple(vc[i].second, (long long)i, -1));
  }
  sort(ev.begin(), ev.end(), cmp);
  queue<int> st;
  int d1 = -1, d2 = -1;
  for (int i = 0; i < ev.size() && d1 == -1; ++i) {
    triple<long long, long long, int> cur = ev[i];
    if (cur.third == 1)
      st.push(cur.second);
    else {
      int top = st.front();
      if (cur.second != top) {
        d1 = cur.second + 1;
        d2 = top + 1;
      } else
        st.pop();
    }
  }
  cout << d1 << " " << d2;
}
int main() {
  ios::sync_with_stdio(0);
  solve();
  return 0;
}
