first we've to map 4 combinations of states and I/P symbol to two states [QxΣ->Q]
[(X, a), (X, b), (Y,a), (Y, b)] --> [X, Y]
so we get $2^4$=16
initial state is X=1 choice
final states we've 2*2 choices
so total 16*2*2*1=64
pls tell where I'm going wrong