import sequtils,strutils
var res = 0
for _ in 1..1000:
  let nk = stdin.readline().split().map(parseInt)
  let (n,k) = (nk[0],nk[1])
  # n - 1 == a * (k + 1) の時敗北
  if (n - 1) mod (k + 1) != 0: res += 1
echo res