#include <bits/stdc++.h>
#define S second
#define F first 
#define MP make_pair
int const N=100001;
using namespace std;
priority_queue<int>q;
int t[N];
int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n,a,b,wyn=0;
	cin>>n;
	for(int i=0;i<n-1;i++){
		cin>>a>>b;
		if(a==1)	q.push(-1*b);
		else{
			if(b<=q.size()){
				while(b<=q.size()){
					q.pop();
				}
			}
		}
	}
	cin>>a>>b;
	if(q.size()>=b){
		while(!q.empty()){
			wyn-=q.top();
			q.pop();
		}
		cout<<wyn;
	}
	else cout<<-1;
}

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NQoxIDEwCjEgMTIKMCAyCjEgMQowIDM=

5
1 10
1 12
0 2
1 1
0 3