mod=998244353
n,k=map(int,input().split())
ans=0
for x in range(1,k+1):
  ans+=x*(k-x)%mod*(pow(x,n-1,mod)-pow(x-1,n-1,mod))%mod*n
  ans%=mod
  #print(x*(k-x)%mod*(pow(x,n-1,mod)-pow(x-1,n-1,mod)))

for x in range(1,k+1):
  tmp=pow(x,n,mod)-n*pow(x-1,n-1,mod)-pow(x-1,n,mod)
  ans+=x*tmp%mod
  ans%=mod

print(ans)