Simplify this boolean expression to the target answer $($top is expression, bottom is the target answer$).$ Show each step in the process $($lable each step$)$

$f_1=(x_1+{\stackrel{}{x}}_0+y_1+y_0)({\stackrel{}{x}}_1+x_0+y_1+y_0)({\stackrel{}{x}}_1+x_0+y_1\frac{+}{b}ar(y{)}_0)({\stackrel{}{x}}_1+{\stackrel{}{x}}_0+y_1+y_0)({\stackrel{}{x}}_1+{\stackrel{}{x}}_0+y_1\frac{+}{b}ar(y{)}_0)({\stackrel{}{x}}_1+{\stackrel{}{x}}_0\frac{+}{b}ar(y{)}_1+y_0)$

$f_1=(y_1+y_0+{\stackrel{}{x}}_0)(y_1+{\stackrel{}{x}}_1)(y_0+{\stackrel{}{x}}_1+{\stackrel{}{x}}_0)$