BEGIN
    low := 15;
    mid := 45;
    high := 50;

    evens  := [0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20];
    odds   := [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21];
    primes := [2, 3, 5, 7, 11, 13, 17, 19, 23, 29];
    teens  := [13..19];
    
    s1 := evens*odds;
    s2 := evens - teens + [high, mid..47, 2*low];
    s3 := evens*primes + teens;
    s4 := s3 - odds;
    s5 := evens + odds + primes + teens;
    s6 := (primes - teens)*odds;

    b1 := odds - primes = [15, 9, 21, 1];
    b2 := teens <= evens + odds;
    b3 := primes >= teens;
    b4 := odds - teens*primes <> [21, 7, 9, 1, 11, 5, 15, 3];
    b5 := 15 IN teens - primes;
END.