#include <bits/stdc++.h>

using namespace std;

ifstream fin("heavymetal.in");
ofstream fout("heavymetal.out");

struct spectacol
{
    int x, y, ind, mod, val;
};

spectacol p[100002];
int n;

inline bool Compar1(spectacol i, spectacol j)
{
    return (i.x <= j.x && i.mod <= j.mod);
}

inline bool Compar2(spectacol i, spectacol j)
{
    return i.ind <= j.ind;
}

int main()
{
    fin >> n;
    for(int i = 1; i <= n; i++)
    {
        fin >> p[i].x >> p[i].y;
        p[i].ind = i;
        p[i].mod = p[i].y - p[i].x;
    }
    sort(p + 1, p + n + 1, Compar1);
    p[1].val = 1;
    for(int i = 2; i <= n; i++)
    {
        if(p[i].x < p[i - 1].y)
            p[i].val = p[i - 1].val;
        else
            p[i].val = p[i - 1].val + 1;
    }
    for(int i = 2; i <= n; i++)
        if(p[i - 1].val == p[i].val && p[i].mod > p[i + 1])
    return 0;
}