With this short piece of code you are going to learn how to subtract the time.
it may be very useful to time your trades entrances and exits, also to make up strategies based on time.

I use a tick counter to execute the subtraction.
Notice that the initial date is: 1970.01.01 00:00:00 and you may use it as a parameter for your calculations.

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To use it just grab it to your chart and you're gonna see the Comment on your screen with such information.