#include<iostream>
#include<cmath>
using namespace std;
int main()
{
    int S[101],h=0,x,n;
    int k,maxn=-1;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>k;
        if(k==0)
        {
            cin>>x;
            S[++h]=x;
        }else
            if(k==1){
            h--;
        }else
        {
            if(h>0){
                for(int j=1;j<=h;j++)
                    maxn=max(maxn,S[j]);
            cout<<maxn<<endl;
            maxn=-1;
            }else
            {
                cout<<"0"<<endl;
            }
            
            
        }
        
    }
    return 0;
}