N = input()

l = len(N)
ans = 0
#各桁を「数字無し（０）」「７（１）」「５（２）」「３（３）」で記述するような4進数を作る
for n in range(1, 4**l):
  n4 = ""
  while n > 0:
    mod = n % 4
    n4 = str(mod) + n4
    n //= 4
  
  if "0" in n4:
    continue
  
  if ("1" in n4) and ("2" in n4) and ("3" in n4):
    n4_10 = ""
    for i in range(len(n4)):
      if n4[i] == "1":
        n4_10 = n4_10 + "7"
      elif n4[i] == "2":
        n4_10 = n4_10 + "5"
      else:
        n4_10 = n4_10 + "3"
    if int(n4_10) =< int(N):
      ans += 1

print(ans)