import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

from collections import deque 

cnt = 0
def include(x):
    global cnt
    s = str(x)
    if ('3' in s) and ('5' in s) and ('7' in s):
        cnt += 1  
     
def main():
    n = int(readline())
    dq = deque()
    dq.append(0)
    cnd = []
    dd = (3, 5, 7)
    while len(dq)>0:
        v = dq.popleft()
        for i in dd:
            if v*10+i>n:
                continue
            dq.append(v*10+i)
            cnd.append(v*10+i)
            include(v*10+i)
        if cnd[-1] > n:
            break
    print(cnt)
if __name__ == '__main__':
    main()
