R programming error Deleting the right column

Question

Hi, I'm new to R programming. Below is my code, it works for the first few variables, but when it comes to the last two variables, it enters an infinite loop and gives me the following error: 

Error in if (maxVar > sl) { : missing value where TRUE/FALSE needed

Code:

backwardElimination <-function(training,sl) {
  numVar=length(training)
  funzRegressor = lm(formula = profit ~.,
               data = training)
  p = summary(funzRegressor)$coefficients[,4]
  maxVar = max(p)
  if (maxVar > sl){
    for (j in c(1:numVar)){
      if (maxVar == p[j]) {
        training = training[, -j]
        backwardElimination(training,sl)
      }
    }
  }
  return(summary(funzRegressor))
}

You can refer the rest of my code:

#importing dataset
dataset = read.csv('50_Startups.csv')


# Encoding categorical data
dataset$State = factor(dataset$State,
                         levels = c('New York', 'California', 'Florida'),
                         labels = c(1, 2, 3))

#splitting in train / test set 
library(caTools)
set.seed(123)
split = sample.split(dataset$Profit, SplitRatio = 4/5)
trainingSet = subset(dataset, split == TRUE)
testSet = subset(dataset, split == FALSE)
#Transforming state in dummy variables
trainingSet$State = factor(trainingSet$State)
dummies = model.matrix(~trainingSet$State)
trainingSet = cbind(trainingSet,dummies)
profit = trainingSet$Profit
trainingSet = trainingSet[, -4]
trainingSet = trainingSet[, -4]
trainingSet = cbind(trainingSet,profit)
#calling the function
SL = 0.05
backwardElimination(trainingSet, SL)