So, first from this to omega e that I will discuss next class, but that is also algebra, but you have to know that, you know because after all depending on how you move, this itself changes and when this changes this combination will call the change. So, this also as an effect on how you actually get tune or you know like just last thing is that supposing a ship sea state 4, there is a peak wave coming at 10 second. Now, if you are going at a different speed that 10 will appear 8 second, and suppose your resonance is 8 seconds, and then you are going to be bad, badly hit, change the speed you make it 9 second, it will not be so bad. So, we will discuss that in next class the the response part at more length. So, today we will end it here, thank you.