Design a sequential circuit with two $JK$ flip$-$flops A and $B$ and two inputs $E$ and $F.$ If $E=0,$ the circuit remains in the same state regardless of the value of $F.$ When $E=1$ and $F=1,$ the circuit goes through the state transitions from $00$ to $01,$ to $10,$ to $11,$ back to $00,$ and repeats. When $E=1$ and $F=0,$ the circuit goes through the state transitions from $00$ to $11,$ to $10,$ to $01,$ back to $00,$ and repeats.