B	A1	A	Y
0	0	0	1
1	0	0	0
1	1	0	0
0	1	0	1
0	1	1	0
1	1	1	0
1	0	1	0
0	0	1	1

function: Y = (!B && !A1 && !A || !B && A1 && !A || !B && !A1 && A)