#include <bits/stdc++.h>
using namespace std;

int main() {
    int n, k;
    cin >> n >> k;

    vector<int> v(n), p(n, 0);
    while(k--) {
        int a, b;
        cin >> a >> b;
        p[a-1] += 1;
        p[b-1] -= 1;
    }

    int s = 0;
    for(int i = 0; i < n; i++) {
        s += p[i];
        v[i] = s;
    }
    sort(v.begin(), v.end());

    cout << v[n/2];

	return 0;
}