Can you show me how to calculate recall to evaluate the model if it returns the right answer or not?

[pedramsalimi]

i want to use ubuntu dialogue corpus which has label column, something like this blog:
http://www.wildml.com/2016/07/deep-learning-for-chatbots-2-retrieval-based-model-tensorflow/

so i want to use this model to train ubuntu dataset but i don't know how to calculate recall.