#include<cstring>
#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n;
long long ans;

struct node{
	int s,t;
}a[200005];

bool comp(node a,node b){
	return a.s<b.s || (a.s==b.s && a.t>b.t);
}

int main(){
	freopen("boarding.in","r",stdin);
	freopen("boarding.out","w",stdout);
	int i;
	scanf("%d",&n);
	for  (i=1;i<=n;i++){
		scanf("%d%d",&a[i].s,&a[i].t);
		a[i].s+=n-i;
	}
	sort(a+1,a+n+1,comp);
	ans=a[1].t;
	for (i=2;i<=n;i++)	
	 if (a[i].s!=a[i-1].s) ans+=a[i].t;
	ans+=a[n].s;
	cout<<ans<<endl;
	return 0;
}