Hi$,$ now I $\text{'}$m Designing a $4-$bit counter that starts to count from $0$ to $9.$ but there is condition. which start counting when it has received an input sequence of $11$ as the $$start$-$counting$$ command. When the counter value has reached $9,$ it turns $0$ and stays there to wait for the arrival of next input the $$start$-$counting$$ command.