#include <iostream>
#include <cmath>
#include <queue>
using namespace std;

int main()
{
    ios_base::sync_with_stdio(false);
    queue<int> q;
    q.push(10);
    q.push(20);
    q.push(20);
    q.push(30);
    q.push(40);
    q.push(50);
    while(!q.empty()) {
        cout << q.front() << endl;
        q.pop();
    }

    return 0;
}