A,B = map(int,input().split())
ans = 0
def is_multi3(x):
    return x%3 == 0

def is_in3(x):
    return '3' in list(str(x))

for i in range(A,B+1):
    if is_multi3(i):
        ans += 1
        continue

    if is_in3(i):
        ans +=1
print(ans)