#include <iostream>
#include <unordered_map>
#include <unordered_set>

using namespace std;

int main() {
    unordered_map<int, unordered_set<int>> tc_ac;//key - turtles count, value - turtles counts after i-th turtle
    size_t operations_count;
    cin >> operations_count;
    for (size_t i = 0; i < operations_count; ++i) {
        int before, after; //turtles count before i-th turtle and turtles count afetr i-th turtle
        cin >> before >> after;
        //if (before < 0 || after < 0) continue;

        tc_ac[before + 1 + after].insert(after);
    }

    int result = tc_ac.begin()->second.size();
    for (const auto& [_, after] : tc_ac) {
        if (after.size() > result) result = after.size();
    }
    cout << result;
}