#include <iostream>
#include <map>
using namespace std;

long long n, biggest;
map<const string, long long> monitors;

int main()
{
	cin >> n;
	for(int i = 0;i < n;i ++)
	{
		string w;
		int h;
		cin >> h >> w;
 		monitors[w] += h;
		if(monitors[w] > biggest)
		{
			biggest = monitors[w];
		}
	}
	
	cout << biggest;
	
	cout << endl;
	return 0;
}
