#include<algorithm>
#include<iostream>
#include<stack>
using namespace std;
int n,h[1000010],v[1000010],f[1000010];
stack<int> s;
int main(){
cin>>n;
for(int i = 1;i <= n;i++)cin>>h[i]>>v[i];
for(int i = n;i >= 1;i--){
while(s.size() && h[i] > h[s.top()])s.pop();
if(s.size())f[s.top()] += v[i];
s.push(i);
}
while(s.size())s.pop();
for(int i = 1;i <= n;i++){
while(s.size() && h[i] > h[s.top()])s.pop();
if(s.size())f[s.top()] += v[i];
s.push(i);
}
cout<<*max_element(f + 1,f + 1 + n);
return 0;
}
