ABC
PPL
DDC
ZEC

ABC
CCD
RL3

list1 <- 1:30
list2 <- 1:40
list3 <- 1:50

n <- 1000
runs <- data.frame(run=1:n,threes=NA,twos=NA)
for(i in 1:n) {
  sample_list1 <-(sample(list1,5, replace=FALSE))
  sample_list2 <-(sample(list2,10, replace=FALSE))
  sample_list3 <-(sample(list3,20, replace=FALSE))

  combined_lists <- c(sample_list1, sample_list2, sample_list3)
  combined_counts <- as.data.frame(table(combined_lists))

  runs$three[i] <- sum(combined_counts$Freq==3)

}

runs

#calculate p value when 994 overlaps observed in real data
pval3 = sum(runs$threee >= 994)/1000