mod=998244353
def modpow(a,b,m):
  res=1
  while b:
    if b%2:
      res*=a
      res%=m
    a*=a
    a%=m
    b//=2
  return res
def powermat(a,n):
  x=len(a)
  b=[[0 for i in range(3)] for j in range(3)]
  c=[[0 for i in range(3)] for j in range(3)]
  for i in range(3):
    b[i][i]=1
  while n:
    if n%2:
      for i in range(3):
        for j in range(3):
          c[i][j]=0
      for i in range(3):
        for j in range(3):
          for k in range(3):
            c[i][j]+=a[i][k]*b[k][j]
      for i in range(3):
        for j in range(3):
          b[i][j]=c[i][j]%mod
    for i in range(3):
      for j in range(3):
        c[i][j]=0
    for i in range(3):
      for j in range(3):
        for k in range(3):
          c[i][j]+=a[i][k]*a[k][j]
    for i in range(3):
      for j in range(3):
        a[i][j]=c[i][j]%mod
    n//=2
  return b
n,q=map(int,input().split())
ans=0
for i in range(1,n):
  x=i*(n-i+1)
  y=n*(n+1)//2-x
  z=(n-i)*(n-i+1)*(n-i+2)//6
  x%=mod
  y%=mod
  z%=mod
  a=[[0 for i in range(3)] for j in range(3)]
  a[1][2]+=z;
  a[2][2]+=n*(n+1)
  a[0][0]+=y
  a[0][0]+=n*(n+1)//2
  a[1][1]+=y;
  a[1][1]+=n*(n+1)//2
  a[1][0]+=x
  a[0][1]+=x
  a=powermat(a,q)
  ans+=a[0][2]
print(ans*modpow(2,mod-2,mod)%mod)