queue

#include <bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    queue<int> q;
    int x;
    int s;
    while(n--){
        cin >> x;
        if(x == 1){
            cin >> s;
            q.push(s);
        }else if(x == 2){
            if(q.empty()){
                printf("impossible!\n");
            }else{
                q.pop();
            }
        }else if(x == 3){
            if(q.empty()){
                printf("impossible!\n");
            }else{
                cout << q.front() << endl;
            }
        }
    }
    return 0;
}