bubble <- function(V,N) {
  i = N
  while (i > 1) {
    j = 1
    while (j < i) {
      if (V[j] > V[j+1]) {
        tmp = V[j]
        V[j] = V[j+1]
        V[j+1] = tmp
      }
      j = j + 1
    }
    i = i - 1
  }
  return(V)
}