#include <iostream>
#include <fstream>
#include <cstdlib>
#include <ctime>
#include <algorithm>

using namespace std;

void varianta_1(unsigned int v[], unsigned int n, unsigned int s)
{
    for(unsigned int i = 0; i < n; i++)
    {
        if(v[i] >= s/2)
            break;

        unsigned int x = s - v[i];

        for(unsigned int j = i + 1; j < n; j++)
        {
            if(v[j] == x)
            {
                cout << v[i] << ' ' << x << endl;
                break;
            }

            if(v[j] > x)
                break;
        }
    }
}

void varianta_2(unsigned int v[], unsigned int n, unsigned int s){

    for(unsigned int i = 0; i < n; i++)
    {
        if(v[i] >= s/2)
            break;

        unsigned int x = s - v[i];

        unsigned int st = i + 1, dr = n-1;
        while (st <= dr){
            unsigned int mij = (st + dr)/2;
            if (v[mij] == x){
                cout << v[i] << ' ' << x << endl;
                break;
            } else {
                if (x < v[mij]){
                    dr = mij-1;
                } else {
                    st = mij + 1;
                }
            }
        }
    }
}

void generareTeste(const char nume_fisier[], unsigned int n)
{
    unsigned int i, vcrt, r, x, y;

    srand(time(NULL));

    ofstream fout(nume_fisier);

    fout << n << endl;
    //primul numar este cuprins intre 1 si 100
    vcrt = 1 + (rand() * rand()) % 100;
    fout << vcrt << " ";

    //restul elementelor vor fi cuprinse intre vcrt+1  si vcrt+1000
    x = y = 0;
    for(i = 1; i < n; i++)
    {
        r = 1 + (rand() * rand()) % 1000;
        vcrt = vcrt + r;

        //sansele ca r >= 500 sunt, teoretic, 50%
        if(r >= 500)
            if(x == 0)
                x = vcrt;
            else if(y == 0)
                y = vcrt;

        fout << vcrt << " ";
    }

    fout << endl << x + y << endl;

    fout.close();
}

void citireDate(const char nume_fisier[], unsigned int v[], unsigned int &n, unsigned int &s)
{
    ifstream fin(nume_fisier);

    fin >> n;
    for(int i = 0; i < n; i++)
        fin >> v[i];
    fin >> s;

    fin.close();
}
unsigned int v[1000000];

int main()
{
    unsigned int n, s;

    generareTeste("preturi.in", 1000000);

    citireDate("preturi.in", v, n, s);

    varianta_1(v, n, s);
    cout << endl;
    varianta_2(v, n, s);

    return 0;
}