#include <bits/stdc++.h>
using namespace std;
 
const int MaxN=2e5;
const int MaxA=2e5;
vector <int> pos[MaxA+1];
int add[MaxN+1]={};
int tag[MaxN+1]={};
 
int main() {
	int N,t,x;
	cin>>N;
	for(int n=1;n<=N;n++){
		cin>>t>>x;
		tag[n]=(t==1)?0:-1;
		if(t==1){
			pos[x].push_back(n);
		}
		if(t==2){
			if(pos[x].empty()){
				cout<<-1;
				return 0;
			}
			add[n]-=1;
			//位置等於n時減少一瓶藥水
			add[pos[x].back()]+=1;
			//位置等於pos[x].back時撿藥水
			tag[pos[x].back()]=1;
			pos[x].pop_back();
		}
	}
	int ans=0,maxans=0;
	for(int n=1;n<=N;n++){
		ans+=add[n];
		maxans=max(ans,maxans);
	}
	cout<<maxans<<"\n";
	for(int n=1;n<=N;n++){
		if(-1<tag[n])
			cout<<tag[n]<<" ";
	}
	return 0;
}

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

MTMKMSAyCjEgMwoxIDEKMSAzCjEgMgoyIDMKMSAzCjEgMwoyIDMKMSAzCjIgMgoyIDMKMiAx

13
1 2
1 3
1 1
1 3
1 2
2 3
1 3
1 3
2 3
1 3
2 2
2 3
2 1