n is 1 n is 2 n mod 100 is 1 n mod 100 is 2 n mod 100 in 3..4 n mod 10 is 1 and n mod 100 is not 11 n mod 10 in 2..4 and n mod 100 not in 12..14 n mod 10 is 0 or n mod 10 in 5..9 or n mod 100 in 11..14 n mod 10 is 1 n mod 10 is 2 n mod 10 in 3..4 n in 0..1 n mod 10 is 1 and n mod 100 is not 11 n mod 10 is 2 and n mod 100 is not 12 n is 0 or n mod 100 is 0 or n mod 100 in 10..19