GATE Electronics and Communications (EC) 2017 Shift 1 Solved Paper

A 4-bit shift register circuit configured for right-shift operation, i.e. D_in → A, A → B, B → C, C → D, is shown. If the present state of the shift register is ABCD = 1101, the number of clock cycles required to reach the state ABCD = 1111 is ________.