n=int(input())
c=0
l=[3,5,7]
L=[]
for i1 in l:
  for i2 in l:
    for i3 in l:
      for i4 in l:
        for i5 in l:
          L.append(10000*i1+1000*i2+100*i3+10*i4+i5)
for i in range(min(n+1,10000)):
  l=str(i)
  if '3' in l and '5' in l and '7' in l:c+=1
for j in L:
  for i in range(j,n+1,100000):
    l=str(i)
    if '3' in l and '5' in l and '7' in l:c+=1
print(c)