#include <bits/stdc++.h>
using namespace std;
const int M = 1005;
int a[M], b[M];
int ans = 0;
typedef pair<int, int> PII;
vector<PII> v;
int main() {
    int N;
    cin >> N;
    for (int i = 0; i < N; i ++ ) {
        int x, y;
        cin >> x >> y;
        b[x]++, b[y]--;
        v.push_back({x, y});
    }
    for (int i = 0; i < N; i ++ ) {
        int res = 0;
        memcpy(a, b, sizeof(b));
        int x = v[i].first, y = v[i].second;
        a[x]--, a[y]++;
        for (int j = 1; j < M ;j ++ ) {
            a[j] += a[j - 1];
        }
        for (int j = 0; j < M ;j ++ ) {
            // !!!
            res += !!a[j];
        }
        ans = max(ans, res);
    }
    cout << ans << endl;
    return 0;
}