If n=a1a2⋯ak−1ak , be s(n) such that
. If k is even, s(n)=a1a2+a3a4⋯+ak−1ak . If k is odd, s(n)=a1+a2a3⋯+ak−1ak For example s(123)=1+23=24 and s(2021)=20+21=41 Be n is digital if s(n) is a divisor of n . Prove that among any 198 consecutive positive integers, all of them less than 2000021 there is one of them that is digital .