parta <- 0
partb <- 0

for (i in 1:10000){
  x1 <- sample(1:6, size = 1)
  x2 <- sample(1:6, size = 1)
  if ((x1+x2) <=6){
    parta <- parta + 1
    if (x1>2){
      partb <- partb + 1
    }
  }
}

proba <- parta/10000
probb <- partb/parta

cat(proba, "\n")
## 0.4192
cat(probb, "\n")
## 0.4055344