How to find optimal number of trees in random forest using Grid search in R?

Question

From below code, I am getting optimal number of mtry. What is this mtry ? and How should I find the optimal number of tree that to be assigned to Random forest algorithm so that it will give High accuracy.

Any comment will be highly appreciated ! Thanks in Advance.

classifier = train(form = Survived ~ ., data = training_set_scaled, method = 'rf')
classifier
classifier$bestTune