Lara Croft and the New Game CodeForces - 976B 水题排序

You are given a sequence a₁, a₂, ..., a_n of one-dimensional segments numbered 1through n. Your task is to find two distinct indices i and j such that segment a_ilies within segment a_j.

Segment [l₁, r₁] lies within segment [l₂, r₂] iff l₁ ≥ l₂ and r₁ ≤ r₂.

Print indices i and j. If there are multiple answers, print any of them. If no answer exists, print -1 -1.

Input

The first line contains one integer n (1 ≤ n ≤ 3·10⁵) — the number of segments.

Each of the next n lines contains two integers l_i and r_i (1 ≤ l_i ≤ r_i ≤ 10⁹) — the i-th segment.

Output

Print two distinct indices i and j such that segment a_i lies within segment a_j. If there are multiple answers, print any of them. If no answer exists, print -1 -1.

Examples

Input

5
1 10
2 9
3 9
2 3
2 9

Output

2 1

Input

3
1 5
2 6
6 20

Output

-1 -1

Note

In the first example the following pairs are considered correct:

• (2, 1), (3, 1), (4, 1), (5, 1) — not even touching borders;
• (3, 2), (4, 2), (3, 5), (4, 5) — touch one border;
• (5, 2), (2, 5) — match exactly.

关于cmp的写法我博客有专门文章讲

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;
#define LL long long int
const int N = 1e5 + 7;
const int MOD = 1e9+7;
struct point
{
    LL l,r,index;
    bool operator < (const point &tmp) const
    {
        return l == tmp.l ? r > tmp.r : l < tmp.l;
    }
} num[300004];

int main()
{
    LL n;
    cin>>n;
    for(LL i=0; i<n; i++)
    {
        scanf("%lld %lld",&num[i].l,&num[i].r);
        //cin>>num[i].l>>num[i].r;
        num[i].index = i + 1;
    }
    //cout<<"1"<<endl;
    sort(num,num+n);
    LL i1=-1,i2=-1;
    for(LL i=1; i<n; i++)
    {
        if(num[i-1].r >= num[i].r )
        {
            i1 = num[i-1].index;
            i2 = num[i].index;
            break;
        }
    }

    cout<<i2<<" "<<i1<<endl;

}