class Combination:
    def __init__(self, n, MOD=998244353):
        self.fact = [1] * (n + 1)
        self.invfact = [1] * (n + 1)
        self.MOD = MOD
        for i in range(1, n + 1):
            self.fact[i] = self.fact[i - 1] * i % MOD

        self.invfact[n] = pow(self.fact[n], MOD - 2, MOD)
        for i in range(n - 1, -1, -1):
            self.invfact[i] = self.invfact[i + 1] * (i + 1) % MOD

    def extend(self, n):
        le = len(self.fact)
        if n < le:
            return
        self.fact.extend([1] * (n - le + 1))
        self.invfact.extend([1] * (n - le + 1))
        for i in range(le, n + 1):
            self.fact[i] = self.fact[i - 1] * i % self.MOD

        self.invfact[n] = pow(self.fact[n], self.MOD - 2, self.MOD)
        for i in range(n - 1, le - 1, -1):
            self.invfact[i] = self.invfact[i + 1] * (i + 1) % self.MOD

    def nPk(self, n, k):
        if k < 0 or n < k:
            return 0
        if n >= len(self.fact):
            self.extend(n)
        return self.fact[n] * self.invfact[n - k] % self.MOD

    def nCk(self, n, k):
        if k < 0 or n < k:
            return 0
        if n >= len(self.fact):
            self.extend(n)
        return (self.fact[n] * self.invfact[n - k] % self.MOD) * self.invfact[k] % self.MOD

    def nHk(self, n, k):
        if n == 0 and k == 0:
            return 1
        return self.nCk(n + k - 1, k)

    def Catalan(self, n):
        return (self.nCk(2 * n, n) - self.nCk(2 * n, n - 1)) % self.MOD


MOD = 998244353

x, y, z, k = map(int, input().split())
Comb = Combination(x + y + z)
ans = 0
n = x + y + z

for i in range(1, y + z + 2):
    mi = min(y + z - i + 1 + k, y + z)
    mi2 = min(y, y + z - mi)
    tmp = pow(mi, mi2, MOD) * Comb.fact[y + z - mi2] % MOD
    tmp *= Comb.nCk(n - i, y + z - (i - 1))
    ans += tmp % MOD

ans %= MOD
ans *= pow(Comb.nCk(n, x) * Comb.fact[y + z] % MOD, MOD - 2, MOD)
print(ans % MOD)