N = int(input())
n = len(str(N)) - 1
ans = 0
for i in range(3, n+1):
  ans += 3**i - (2**i)*3 + 3

t = 3**n - 2**(n+1) + 1
m = 3**(n-1) - 2**n + 1

if int(str(N)[0]) == 3:
  if int(str(N)[1]) == 3:
    for i in range(33*(10**(n-1)), N+1):
      s = set([j for j in str(i)])
      if ('5' in s) and ('7' in s) and (len(s)==3):
        ans += 1
  elif int(str(N)[1]) == 4:
    ans += m
  elif int(str(N)[1]) == 5:
    ans += m
    for i in range(35*(10**(n-1)), N+1):
      s = set([j for j in str(i)])
      if ('5' in s) and ('7' in s) and (len(s)==3):
        ans += 1
  elif int(str(N)[1]) == 6:
    ans += 2*m
  elif int(str(N)[1]) == 7:
    ans += 2*m
    for i in range(37*(10**(n-1)), N+1):
      s = set([j for j in str(i)])
      if ('5' in s) and ('7' in s) and (len(s)==3):
        ans += 1
  elif int(str(N)[1]) > 7:
    ans += 3*m
elif int(str(N)[0]) == 4:
  ans += t
elif int(str(N)[0]) == 5:
  if int(str(N)[1]) == 3:
    for i in range(53*(10**(n-1)), N+1):
      s = set([j for j in str(i)])
      if ('5' in s) and ('7' in s) and (len(s)==3):
        ans += 1
  elif int(str(N)[1]) == 4:
    ans += m
  elif int(str(N)[1]) == 5:
    ans += m
    for i in range(55*(10**(n-1)), N+1):
      s = set([j for j in str(i)])
      if ('5' in s) and ('7' in s) and (len(s)==3):
        ans += 1
  elif int(str(N)[1]) == 6:
    ans += 2*m
  elif int(str(N)[1]) == 7:
    ans += 2*m
    for i in range(57*(10**(n-1)), N+1):
      s = set([j for j in str(i)])
      if ('5' in s) and ('7' in s) and (len(s)==3):
        ans += 1
  elif int(str(N)[1]) > 7:
    ans += 3*m
elif int(str(N)[0]) == 6:
  ans += 2*t
elif int(str(N)[0]) == 7:
  if int(str(N)[1]) == 3:
    for i in range(73*(10**(n-1)), N+1):
      s = set([j for j in str(i)])
      if ('5' in s) and ('7' in s) and (len(s)==3):
        ans += 1
  elif int(str(N)[1]) == 4:
    ans += m
  elif int(str(N)[1]) == 5:
    ans += m
    for i in range(75*(10**(n-1)), N+1):
      s = set([j for j in str(i)])
      if ('5' in s) and ('7' in s) and (len(s)==3):
        ans += 1
  elif int(str(N)[1]) == 6:
    ans += 2*m
  elif int(str(N)[1]) == 7:
    ans += 2*m
    for i in range(77*(10**(n-1)), N+1):
      s = set([j for j in str(i)])
      if ('5' in s) and ('7' in s) and (len(s)==3):
        ans += 1
  elif int(str(N)[1]) > 7:
    ans += 3*m
elif int(str(N)[0]) > 7:
  ans += 3*t
print(ans)
