def main():
    min_val, max_val = [int(val) for val in input().split()]
    answer = 0

    for val in range(min_val, max_val):
        if (val % 3) == 0 or (str(val).find('3')) >= 0:
            answer += 1
    
    print(answer)

if __name__ == '__main__':
    main()