0 2 0 0 	input 2 ->15
3 4 0 0 	input 4 ->35
6 98 0 100 	skip 2,100
9 112 0 0	return

100 100 0 200	skip 4,200
103 112 0 0	return

200 18 0 0	clear 2 
203 112 0 0	return