# Arup Guha
# 2/24/2024
# Solution to SER D2 Problem G: Rampant Growth

MOD = 998244353

# Returns the result for r rows, c columns.
def solve(r,c):

    # Any slot.
    if c == 1:
        return r

    # Can't do it.
    if r == 1:
        return 0

    # First column has r options.
    res = r

    # All future columns have r-1 options. 
    for i in range(c-1):
        res = (res*(r-1))%MOD
    return res

# Run it.
toks = input().split()
r = int(toks[0])
c = int(toks[1])
print(solve(r,c))