#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <sstream>
#include <vector>
#include <complex>
#include <ctime>
#include <stack>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> VI;
typedef vector< VI > VVI;
typedef pair<int, int> PII;
typedef vector<PII> VPII;

#define REP(i, n) for(int i = 0; i < (n); ++i)
#define RREP(i, n) for(int i = (n) - 1; i >= 0; --i)
#define FOR(i, x, y) for(int i = (x); i <= (y); ++i)
#define RFOR(i, x, y) for(int i = (x); i >= (y); --i)
#define SZ(a) (int)(a).size()
#define ALL(a) (a).begin(),(a).end()
#define SORT(a) sort(ALL(a))
#define CLEAR(x) memset(x, 0, sizeof x);
#define COPY(FROM, TO) memcpy(TO, FROM, sizeof TO);
#define UNIQUE(c) SORT(c),(c).resize(unique(ALL(c))-(c).begin())
#define pb push_back
#define mk make_pair
#define sqr(x) ((x)*(x))
#define X first
#define Y second
const long double pi=acos(-1.0);
const double EPS = 1E-9;
const int INF = (1e+9);
const int NMAX = 31625;
const int MOD = 1743;

int n, k;
vector<pair<PII, int> > arr;
struct aaa{
  int l, r, n;
  aaa (pair<PII, int>  val_) {
    l = val_.X.X;
    r = val_.X.Y;
    n = val_.Y;
  }
  bool operator< (const aaa& rhs) const {
    return r <= rhs.r;
  }
};
set<aaa> st;
int main () {
  freopen ("ancient.in", "r", stdin);
  freopen ("ancient.out", "w", stdout);
  cin >> n;
  arr.resize(n);
  REP (i, n) {
    cin >> arr[i].X.X >> arr[i].X.Y;
    arr[i].Y = i;
  }
  SORT(arr);
  int minn = INF;
  int s1 = -1, s2 = -1;
  REP (i, n) {
    if (!st.empty()) {
      aaa top(*st.begin());
      int intersect = min(top.r, arr[i].X.Y) - arr[i].X.X;
      if (intersect <= 0)
        st.erase(st.begin());
      else if (minn > intersect) {
        minn = intersect;
        s1 = arr[i].Y, s2 = top.n;
      }
    }
    st.insert (aaa(arr[i]));
  }
  if (s1 < 0)
    cout << 0;
  else
    cout << s1 + 1 << " " << s2 + 1;
}
/*
6
1 3 5 7 11 13
5
*/