48 months

1 4 years old	2 4 years old	3 4 years old	4 4 years old
5 4 years old	6 4 years old	7 4 years old	8 4 years old
9 4 years old	10 4 years old	11 4 years old	12 4 years old
13 4 years old	14 4 years old	15 4 years old	16 4 years old
17 4 years old	18 4 years old	19 4 years old	20 4 years old
21 4 years old