#include <iostream>

using namespace std;

int main() {
	int n;
	cin >> n;
	int T_start = 0;
	char* cnt = new char[1000002];
	int T_end = 0;

	for (int i = 0; i < 1000002; i++) {
		cnt[i] = 0;
	}

	int s = 0;
	int max = 0;
	for (int i = 0; i < n; ++i) {
		int l;
		cin >> T_start >> l;
		T_end = T_start + l;
		for (int j = T_start; j < T_end; ++j) {
			cnt[j]++;
			if (cnt[j] > max) {
				max = cnt[j];
			}
		}
	}

	cout << max;
	return 0;
}