Buggy python submission (verdict: Time Limit Exceeded):
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r):
    r = min(n-r,r)
    if r == 0: return 1
    over = reduce(modmul, range(n, n - r, -1))
    under = reduce(modmul, range(1,r + 1))
    return over * modinv(under, 998244353)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    for i in range(K+1):
        ans = (ans + (comb(N-1,i)*M*pow(M-1,N-i-1,998244353))) % 998244353
    print(ans)

Fixed submission:
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r,m):
    if r == 0: return 1
    return memf[n]*pow(memf[r],m-2,m)*pow(memf[n-r],m-2,m)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp
def memfact(a):
    temp = 1
    yield temp
    for i in range(1,a+1):
        temp = temp * i % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
memp = []
memf = []
mpappend = memp.append
mfappend = memf.append
for x in mempow(M-1,N-1):
    mpappend(x)
for x in memfact(N-1):
    mfappend(x)
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    i = 0
    for i in range(K+1):
        ans = (ans + (comb(N-1,i,998244353)*M*memp[N-i-1])) % 998244353
    print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r):
    r = min(n-r,r)
    if r == 0: return 1
    over = reduce(modmul, range(n, n - r, -1))
    under = reduce(modmul, range(1,r + 1))
    return over * modinv(under, 998244353)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
mem = []
mappend = mem.append
for x in mempow(M-1,N-1):
    mappend(x)
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    for i in range(K+1):
        ans = (ans + (comb(N-1,i)*M*pow(M-1,N-i-1,998244353))) % 998244353
    print(ans)

Fixed submission:
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r,m):
    if r == 0: return 1
    return memf[n]*pow(memf[r],m-2,m)*pow(memf[n-r],m-2,m)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp
def memfact(a):
    temp = 1
    yield temp
    for i in range(1,a+1):
        temp = temp * i % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
memp = []
memf = []
mpappend = memp.append
mfappend = memf.append
for x in mempow(M-1,N-1):
    mpappend(x)
for x in memfact(N-1):
    mfappend(x)
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    i = 0
    for i in range(K+1):
        ans = (ans + (comb(N-1,i,998244353)*M*memp[N-i-1])) % 998244353
    print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r):
    r = min(n-r,r)
    if r == 0: return 1
    over = reduce(modmul, range(n, n - r, -1))
    under = reduce(modmul, range(1,r + 1))
    return over * modinv(under, 998244353)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
mem = []
mappend = mem.append
for x in mempow(M-1,N-1):
    mappend(x)
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    for i in range(K+1):
        ans = (ans + (comb(N-1,i)*M*pow(M-1,N-i-1,998244353))) % 998244353
    print(ans)

Fixed submission:
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r,m):
    if r == 0: return 1
    return memf[n]*pow(memf[r],m-2,m)*pow(memf[n-r],m-2,m)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp
def memfact(a):
    temp = 1
    yield temp
    for i in range(1,a+1):
        temp = temp * i % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
memp = []
memf = []
mpappend = memp.append
mfappend = memf.append
for x in mempow(M-1,N-1):
    mpappend(x)
for x in memfact(N-1):
    mfappend(x)
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    i = 0
    for i in range(K+1):
        ans = (ans + (comb(N-1,i,998244353)*M*memp[N-i-1])) % 998244353
    print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r):
    r = min(n-r,r)
    if r == 0: return 1
    over = reduce(modmul, range(n, n - r, -1))
    under = reduce(modmul, range(1,r + 1))
    return over * modinv(under, 998244353)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
mem = []
mappend = mem.append
for x in mempow(M-1,N-1):
    mappend(x)
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    for i in range(K+1):
        ans = (ans + (comb(N-1,i)*M*mem[N-i-1])) % 998244353
    print(ans)

Fixed submission:
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r,m):
    if r == 0: return 1
    return memf[n]*pow(memf[r],m-2,m)*pow(memf[n-r],m-2,m)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp
def memfact(a):
    temp = 1
    yield temp
    for i in range(1,a+1):
        temp = temp * i % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
memp = []
memf = []
mpappend = memp.append
mfappend = memf.append
for x in mempow(M-1,N-1):
    mpappend(x)
for x in memfact(N-1):
    mfappend(x)
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    i = 0
    for i in range(K+1):
        ans = (ans + (comb(N-1,i,998244353)*M*memp[N-i-1])) % 998244353
    print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r):
    r = min(n-r,r)
    if r == 0: return 1
    over = reduce(modmul, range(n, n - r, -1))
    under = reduce(modmul, range(1,r + 1))
    return over * modinv(under, 998244353)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
mem = []
for x in mempow(M-1,N-1):
    mem.append(x)
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    for i in range(K+1):
        ans = (ans + (comb(N-1,i)*M*mem[N-i-1])) % 998244353
    print(ans)

Fixed submission:
from functools import reduce
import math
def xgcd(a, b):
    x0, y0, x1, y1 = 1, 0, 0, 1
    while b != 0:
        q, a, b = a // b, b, a % b
        x0, x1 = x1, x0 - q * x1
        y0, y1 = y1, y0 - q * y1
    return a, x0, y0
def modinv(a, m):
    g, x, y = xgcd(a, m)
    return x % m
def modmul(a,b):
    return a * b % 998244353
def comb(n,r,m):
    if r == 0: return 1
    return memf[n]*pow(memf[r],m-2,m)*pow(memf[n-r],m-2,m)
def mempow(a,b):
    temp = 1
    yield temp
    for i in range(b):
        temp = temp * a % 998244353
        yield temp
def memfact(a):
    temp = 1
    yield temp
    for i in range(1,a+1):
        temp = temp * i % 998244353
        yield temp

N,M,K = (int(x) for x in input().split())
memp = []
memf = []
mpappend = memp.append
mfappend = memf.append
for x in mempow(M-1,N-1):
    mpappend(x)
for x in memfact(N-1):
    mfappend(x)
ans = 0
if M == 1:
    if K + 1 < N:
        print('0')
    else:
        print('1')
else:
    i = 0
    for i in range(K+1):
        ans = (ans + (comb(N-1,i,998244353)*M*memp[N-i-1])) % 998244353
    print(ans)