N = int(input())
count = 0

for i in range(len(str(N))):
    for j in range(3 * (10**i), 8 * (10**i)):
        if j > N:
            break
        if '0' not in str(j) and '1' not in str(j) and '2' not in str(j) and '4' not in str(j) and '6' not in str(j) and '8' not in str(j) and '9' not in str(j) and('7' in str(j) and '5' in str(j) and '3' in str(j)):
            count += 1

print(count)