vector

#include<bits/stdc++.h>
using namespace std;
int n,x;char c;vector<int>a;
int main(){
    cin>>n;
    while(n--){
        cin>>c;
        if(c=='I')cin>>x,a.push_back(x);
        else a.pop_back();
    }
    for(auto v:a){
        cout<<v<<" ";
    }
    return 0;
}