def main():

    n = list(map(int, input().split()))
    #print(n)

    sample = ["23", "24", "25"]

    count = 0
    for i in range(n[0], n[1] + 1):
        #print(i)
        if str(i) in sample:
            count += 1          
            
  
        #if 

    print(3 - count)



if __name__ == '__main__':
    main()