
#include 
#include 

using namespace std;

void reducirCola(queue  &c);

int main(){
    queue  c;

    c.push(1);
    c.push(1);
    c.push(1);
    c.push(2);
    c.push(2);
    c.push(2);
    c.push(3);
    c.push(3);
    c.push(3);

    reducirCola(c);

    while (!c.empty()){
        cout << c.front() << endl; c.pop();
    }

    return 0;
}

void reducirCola(queue  &c){
    queue  q;
    int x, y, z;

    if (!c.empty()){
        x = c.front(); c.pop();
        q.push(x);

        while (!c.empty()){
            y = c.front(); c.pop();

            if (x != y){
                q.push(y);
                x = y;
            }
        }
    }

    while (!q.empty()){
        z = q.front(); q.pop();
        c.push(z);
    }
}