#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;
unsigned long long a[100000],b[100000],sum[100000];
int main()
{
    unsigned long long n,i,j,k=0;
    cin>>n;
    for (i=0;i<n;i++)
        cin>>b[i]>>a[i];
    for (i=0;i<n-1;i++)
        for (j=0;j<n-i-1;j++)
            if (a[j]<a[j+1]) {swap(a[j],a[j+1]); swap(b[j],b[j+1]);}
    for (i=0;i<n;i++)
    {
        sum[k]=b[i];
        for (j=i+1;j<n;j++)
        {
            if (a[j]==a[i]) sum[k]+=b[j];
            else break;
        }
        k++;
    }
    sort(sum,sum+k);
    cout<<sum[k-1]<<endl;
    return 0;
}