C B A->Y 0 0 0 Y=1 1 0 0 Y=0 1 1 0 Y=0 0 1 0 Y=1 0 1 1 Y=0 1 1 1 Y=0 1 0 1 Y=0 0 0 1 Y=1 function: Y = (!C && !B && !A || !C && B && !A || !C && !B && A)