#include <iostream>

using namespace std;
void clear_mesiv(int*a,int razmer)
{
    for (int i=0;i<razmer; i++)
        a[i]=0;
}
/*int proverka(int*a, int razmer)
{
    int i;
    for (i=0;i<razmer;i++)
        if (a[i]==0)
            return 1;
    if (i==razmer-1)
        return 0;
}*/
void unshift(int* a,int razmer,int& ukazatel_shift, int newelement)
{
    while (a[ukazatel_shift]!=0)
    {
        if(ukazatel_shift!=razmer-1)
        {
            ukazatel_shift++;
        }
        else
            ukazatel_shift=0;
    }
    a[ukazatel_shift]=newelement;
    if(ukazatel_shift!=razmer-1)
    {
        ukazatel_shift++;
    }
    else
        ukazatel_shift=0;
}
int shift(int*a,int razmer,int& ukazatel_shift)
{
    if (ukazatel_shift!=0)
    {
        ukazatel_shift--;
    }
    else
        ukazatel_shift=razmer-1;
    return a[ukazatel_shift];
}

void push(int* a,int razmer,int& ukazatel_pop, int newelement)
{
    while (a[ukazatel_pop]!=0)
    {
        if (ukazatel_pop!=0)
        {
            ukazatel_pop--;
        }
        else
            ukazatel_pop=razmer-1;
    }
    a[ukazatel_pop]=newelement;
    if (ukazatel_pop!=0)
    {
        ukazatel_pop--;
    }
    else
        ukazatel_pop=razmer-1;
}
int pop(int* a,int razmer,int& ukazatel_pop)
{
    if (ukazatel_pop!=razmer-1)
    {
        ukazatel_pop++;
    }
    else
        ukazatel_pop=0;
    return a[ukazatel_pop];
}


int main()
{
    int a[10];
    int ukazatel_shift=0;
    int ukazatel_pop=9;
    int k=0;
    int chetchik=0;
    clear_mesiv(a,10);
    while (k!=1)
    {
        int c;
        int b;
        cin >> b;
        if(chetchik<=10)
        {
            if (b==1)
            {
                cout << "unshift: ";
                cin >> c;
                unshift(a,10,ukazatel_shift,c);
                chetchik++;
            }
            if (b==3)
            {
                cout << "push: ";
                cin >> c;
                push(a,10,ukazatel_pop,c);
                chetchik++;
            }
        }
        else
        cout << "function 1 and 3 nedostupna " << endl;
        if (b==0)
        {
            cout << "shift: " << shift(a,10,ukazatel_shift) << endl;
        }
        if (b==2)
        {
            cout << "pop: " << pop(a,10,ukazatel_pop) << endl;
        }
       // cout << "Ukazatel Shift: " << ukazatel_shift << endl;
       // cout << "Ukazatel Shift: " << ukazatel_pop << endl;
    }
}