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