#include <iostream>
#include <algorithm>
#define N 100000
using namespace std;
struct resolution
{
	long long w,h;	
} monitors[N];
bool compare(resolution a,resolution b)
{
	if(a.h==b.h)return a.w>b.w;
	return a.h>b.h;
}

int main()
{
	long long n;
	cin>>n;
	for(long long i=0;i<n;i++)
	{
		cin>>monitors[i].w>>monitors[i].h;
	}
	sort(monitors,monitors+n,compare);
	long long s=monitors[0].w;
	long long max=0;
	for(long long i=1;i<n;i++)
	{
		if(monitors[i].h==monitors[i-1].h)s+=monitors[i].w;
		else {if(s>max)max=s;s=monitors[i].w;}
	}
	cout<<max<<endl;
	return 0;
}
