import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

mod = 998244353

def pow_sum(r, n):
    if r == 1:
        return n
    else:
        return (pow(r, n, mod)-1) * pow(r - 1, mod-2, mod) % mod

n, m = na()

# for i in range(1, n + 1):
#     ans = 0
#     for x in range(1, m + 1):
#         ans += pow(x, i, mod)
#         ans %= mod
#     print(ans * pow(m, n - i, mod) % mod)


ans = 0
for x in range(1, m + 1):
    r = x * pow(m, mod-2, mod) % mod
    # print(x * pow_sum(x, n) % mod)
    ans += r * pow_sum(r, n) % mod
    ans %= mod

print(ans * pow(m, n, mod) % mod)