#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl puts("")
#define X (int)6e6+100
int n,bg,ed,num;
struct node{
	int f,s;
}c;
vector<node> a; 
vector<int> t;
bool cmp(node a,node b){
	return a.f==b.f?a.s>=b.s:a.f<=b.f;
} 
bool cmp2(int a,int b){
	return a>b;
} 
int ans;
signed main(){
//	freopen(".in","r",stdin);
//	freopen(".out","w",stdout);
	scanf("%lld",&n);
	for(int i = 1;i<=n;i++){
		scanf("%lld",&c.f); 
		scanf("%lld",&c.s);
		a.push_back(c);
	}
	sort(a.begin(),a.end(),cmp);
	for(int i = 0;i<n;i++){
		if(i==0||a[i].f!=a[i-1].f){
			t.push_back(a[i].s);
		}else t.push_back(a[i].s/2);
	}
	sort(t.begin(),t.end(),cmp2);
	printf("%lld ",t[0]+t[1]);
	return 0;
}