自己看

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll ans1,ans2;
ll n,ma=-1e18;
struct node{
	ll x;
	ll y;  
}a[300010];
bool cmp(node x,node y){
	return x.y>y.y;
}
int main(){
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	std::cout.tie(nullptr);
	cin>>n;
	for(ll i=1;i<=n;i++) cin>>a[i].x>>a[i].y;
	sort(a+1,a+n+1,cmp);
	ll ans=0;
	if(a[1].x!=a[2].x){
		ans=a[1].y+a[2].y;
	}else{
		ans1=a[1].y+a[2].y/2;
		ll cnt=1;
		while(a[cnt].x==a[1].x) cnt++;
		ans2=a[1].y+a[cnt].y;
		ans=max(ans1,ans2);
	}
	cout<<ans<<endl;
	//fclose(stdin);
	//fclose(stdout);
	return 0;
}
//coder::by::M91