11057

#include<stdio.h>

int main()
{
    long c,a[10005],p,i,j,ln,t,tm,mx,f,k,ai,aj,p1,p2;
    while( scanf("%ld\n",&c) != EOF)
    {
        i=0;
        for(k=0; k<c; k++)
        {
            scanf("%ld",&a[i]);
            i++;
        }
        scanf("%ld",&p);
        ln = i;
        mx = 0;
        f = 0;
        p1 = 0;
        p2 = 0;
        for(i=0; i<ln; i++)
        {
            t = p - a[i];
            for(j=i+1; j<ln; j++)
            {
                if( a[j] == t)
                {
                    ai = a[i];
                    aj = a[j];
                    if( ai >= aj)
                    {
                        tm = ai;
                        ai = aj;
                        aj = tm;
                    }
                    if( f == 1)
                    {
                        if( mx <= (aj - ai))
                        {
                            mx = aj - ai;
                            continue;
                        }
                    }
                    p1 = ai;
                    p2 = aj;
                    mx = aj - ai;
                    f=1;
                }
            }
        }
        printf("Peter should buy books whose prices are %ld and %ld.\n\n",p1,p2);
    }
    return 0;
}