#include<iostream>
#include<algorithm>
using namespace std;
int main(){
	int n;
	cin>>n;
	pair <int, int> size[n];
	long long max=0,lenght=0,nowh;
	for (int i=0;i<n;i++){
		cin>>size[i].second>>size[i].first;
	}
	sort(size,size+n);
	nowh=size[0].first;
	for (int i=0;i<n;i++){
		if (size[i].first==nowh){
			lenght+=size[i].second;
		}else{
			if (max<lenght){
				max=lenght;
			}
			lenght=size[i].second;
			nowh=size[i].first;
		}
	}
	if (max<lenght){
		max=lenght;
	}
	cout<<max<<endl;
	return 0;
}
