#include<iostream>
using namespace std;
int main() {
    long long max=0,monH[100000],monL[100000],broy,sbor[10000];
cin>>broy;
    for(long long br=0; br<broy; br++) {
        cin>>monL[br]>>monH[br];
        sbor[monH[br]]=0;
    }
    for(long long br=0; br<broy; br++) {
        sbor[monH[br]]=sbor[monH[br]]+monL[br];
    }
    for(long long br=0; br<broy; br++) {
		if(max<sbor[monH[br]]){
		max=sbor[monH[br]];	
		}
    }
cout<<max;




    return 0;
}
