How can I count repeating characters in R

I made a random simulation of Roulette

set.seed(101)
n=10000


black <- sample("black",size=n, replace=TRUE)
red <- sample("red",size=n, replace=TRUE)
green <- sample("green",size=n, replace=TRUE)

roulette_table=matrix(NaN,n,1) 

for (i in 1:n) {
temp = runif(1, 0, 1) # uniform between 0 and 1
# determines the probability
if (temp<0.04) { 
  roulette_table [i,1]=green[i] 
} else if (temp>0.04 & temp<0.52) { 
  roulette_table[i,1]=red[i]
}  else  {
  roulette_table[i,1]=black[i] 
} 
  }

How can i count the frequency of repeating characters ? Thanks