timer
S1
S2
S3
S4
N3
N3
N4
N6
N7
N8
N9
N10
N11
N12
N14
N16
N17
N18
N20
N21
N23
N24
N26
N27
N29
N30
N1
N1
N2
N3
N4
N5
N6
N7
N8
N9
N10
N11
N12
N13
N14
N15
N16
N17
N18
N19
N20
N21
N22
N23
N24
N25
N26
N27
N28
N29
N30
N31