How to solve undetected event using AND operator inside EPL statement?

If I have event sequence of: 1:17 2:18 3:17,18 4:2

The sequence of 17--> 18 --> 17 AND 18 should produce derived event of 303 class.

My EPL statement: SELECT a.Identifier, a.SensorValue FROM pattern [every a=GenericSensor(SensorValue=17) -> b=GenericSensor(SensorValue=18) -> c=GenericSensor((SensorValue=17) AND (SensorValue=18))].win:length(4);

My Problem: The derived event of 303 is undetected though there have the true sequence.

How to solve this problem.? I thought the statement is supposedly correct. Thanks in advanced.