#line 1 "/home/y_midori/cp/test/test.test.cpp"
#define PROBLEM "https://yukicoder.me/problems/no/2459"
#line 2 "template.hpp"
// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
template <class T>
concept Streamable = requires(ostream os, T &x) { os << x; };
template <class mint>
concept is_modint = requires(mint &x) {
    { x.val() } -> std::convertible_to<int>;
};
#ifdef LOCAL
#include <debug.hpp>
#else
#define debug(...)
#endif

template <Streamable T> void print_one(const T &value) { cout << value; }
template <is_modint T> void print_one(const T &value) { cout << value.val(); }
void print() { cout << '\n'; }
template <class T, class... Ts> void print(const T &a, const Ts &...b) {
    print_one(a);
    ((cout << ' ', print_one(b)), ...);
    cout << '\n';
}
template <ranges::range Iterable>
    requires(!Streamable<Iterable>)
void print(const Iterable &v) {
    for(auto it = v.begin(); it != v.end(); ++it) {
        if(it != v.begin())
            cout << " ";
        print_one(*it);
    }
    cout << '\n';
}
using ll = long long;
using vl = vector<ll>;
using vll = vector<vl>;
using P = pair<ll, ll>;
#define all(v) v.begin(), v.end()
#define UNIQUE(v) ranges::sort(v), v.erase(unique(all(v)), end(v))
template <typename T> inline bool chmax(T &a, T b) {
    return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
    return ((a > b) ? (a = b, true) : (false));
}
// https://trap.jp/post/1224/
template <class... T> constexpr auto min(T... a) {
    return min(initializer_list<common_type_t<T...>>{a...});
}
template <class... T> constexpr auto max(T... a) {
    return max(initializer_list<common_type_t<T...>>{a...});
}
template <class... T> void input(T &...a) { (cin >> ... >> a); }
template <class T> void input(vector<T> &a) {
    for(T &x : a)
        cin >> x;
}
#define INT(...)                                                               \
    int __VA_ARGS__;                                                           \
    input(__VA_ARGS__)
#define LL(...)                                                                \
    long long __VA_ARGS__;                                                     \
    input(__VA_ARGS__)
#define STR(...)                                                               \
    string __VA_ARGS__;                                                        \
    input(__VA_ARGS__)
#define REP1(a) for(ll i = 0; i < a; i++)
#define REP2(i, a) for(ll i = 0; i < a; i++)
#define REP3(i, a, b) for(ll i = a; i < b; i++)
#define REP4(i, a, b, c) for(ll i = a; i < b; i += c)
#define overload4(a, b, c, d, e, ...) e
#define rep(...) overload4(__VA_ARGS__, REP4, REP3, REP2, REP1)(__VA_ARGS__)
#define rep1(i, n) for(ll i = 1; i <= ((ll)n); ++i)

ll inf = 3e18;
vl dx = {1, -1, 0, 0};
vl dy = {0, 0, 1, -1};
#line 3 "math/factorial.hpp"
// https://suisen-cp.github.io/cp-library-cpp/library/math/factorial.hpp
template <class T> struct factorial {
    factorial() {};
    void ensure(const int n) {
        int sz = size(fac);
        if(sz > n) {
            return;
        }
        int new_sz = max(2 * sz, n + 1);
        fac.resize(new_sz), fac_inv.resize(new_sz);
        for(int i = sz; i < new_sz; i++) {
            if(i == 0) {
                fac[i] = 1;
                continue;
            }
            fac[i] = fac[i - 1] * i;
        }
        fac_inv[new_sz - 1] = T(1) / fac[new_sz - 1];
        for(int i = new_sz - 2; i >= sz; i--) {
            fac_inv[i] = fac_inv[i + 1] * (i + 1);
        }
        return;
    }
    T get(int i) {
        ensure(i);
        return fac[i];
    }
    T operator[](int i) { return get(i); }
    T inv(int i) {
        ensure(i);
        return fac_inv[i];
    }
    T binom(int n, int i) {
        if(n < 0 || i < 0 || n < i) {
            return T(0);
        }
        ensure(n);
        return fac[n] * fac_inv[i] * fac_inv[n - i];
    }
    T perm(int n, int i) {
        if(n < 0 || i < 0 || n < i) {
            return T(0);
        }
        ensure(n);
        return fac[n] * fac_inv[n - i];
    }

  private:
    vector<T> fac, fac_inv;
};
#line 3 "poly/formal-power-series.hpp"
#include <atcoder/convolution>
// 10^9+7みたいなときconvolutionどうする？
template <class mint> struct FormalPowerSeries : vector<mint> {
    using vector<mint>::vector;
    using FPS = FormalPowerSeries;
    FormalPowerSeries(const vector<mint> &v) : vector<mint>(v) {}
    FPS &operator+=(const FPS &f) {
        if(this->size() < f.size())
            this->resize(f.size());
        for(int i = 0; i < ssize(f); ++i)
            (*this)[i] += f[i];
        return *this;
    }
    FPS &operator-=(const FPS &f) {
        if(this->size() < f.size())
            this->resize(f.size());
        for(int i = 0; i < ssize(f); ++i)
            (*this)[i] -= f[i];
        return *this;
    }
    FPS &operator*=(const FPS &f) {
        return (*this) = atcoder::convolution(*this, f);
    }
    FPS &operator*=(const mint &x) {
        for(mint &vi : *this)
            vi *= x;
        return *this;
    }
    FPS operator+(const FPS &f) const { return FPS(*this) += f; }
    FPS operator-(const FPS &f) const { return FPS(*this) -= f; }
    FPS operator*(const FPS &f) const { return FPS(*this) *= f; }
    FPS operator*(const mint &x) const { return FPS(*this) *= x; }
    FPS operator-() const {
        FPS res = *this;
        for(mint &vi : res) {
            vi = -vi;
        }
        return res;
    }
    FPS operator>>(const int sz) const {
        if(sz >= ssize(*this))
            return {};
        FPS res(begin(*this) + sz, end(*this));
        return res;
    }
    FPS operator<<(const int sz) const {
        FPS res(sz, 0);
        res.insert(end(res), begin(*this), end(*this));
        return res;
    }
    FPS inv(int deg = -1) const {
        assert(!this->empty() and (*this)[0] != mint(0));
        if(deg == -1)
            deg = this->size();
        FPS res = {(*this)[0].inv()};
        FPS f;
        f.reserve(this->size());
        for(int d = 1; d < deg << 1; d <<= 1) {
            while(ssize(f) < min(ssize(*this), d))
                f.emplace_back((*this)[f.size()]);
            res *= (FPS({2}) - f * res);
            while(ssize(res) > min(d, deg))
                res.pop_back();
        }
        return res;
    }
    // なければ空を返す
    // 定数項が1でないときget_sqrtを渡す。解が複数ありうることに注意
    FPS sqrt(
        int deg = -1,
        function<mint(mint)> get_sqrt = [](mint) { return mint(1); }) const {
        if(this->empty())
            return {};
        if(deg == -1)
            deg = this->size();
        if((*this)[0] == mint(0)) {
            for(int i = 1; i < ssize(*this); ++i) {
                if((*this)[i] == mint(0))
                    continue;
                if(i & 1)
                    return {};
                if(i / 2 >= deg)
                    break;
                FPS res = (*this >> i).sqrt(deg - i / 2, get_sqrt);
                if(res.empty())
                    return {};
                res = res << (i / 2);
                return res;
            }
            return FPS(deg, 0);
        }
        FPS res{get_sqrt((*this)[0])};
        if(res[0] * res[0] != (*this)[0])
            return {};
        FPS f;
        f.reserve(this->size());
        mint inv2 = mint(1) / mint(2);
        for(int d = 1; d < deg << 1; d <<= 1) {
            while(ssize(f) < min(ssize(*this), d))
                f.emplace_back((*this)[f.size()]);
            res = (res + f * res.inv(d)) * inv2;
            while(ssize(res) > min(d, deg))
                res.pop_back();
        }
        return res;
    }
    FPS diff() const {
        FPS res(max<int>(0, ssize(*this) - 1));
        for(int i = 1; i < ssize(*this); ++i)
            res[i - 1] = (mint)i * (*this)[i];
        return res;
    }
    FPS integral() const {
        FPS res(ssize(*this) + 1);
        for(int i = 0; i < ssize(*this); ++i)
            res[i + 1] = (*this)[i] / mint(i + 1);
        return res;
    }
    FPS log(int deg = -1) const {
        assert(!this->empty() and (*this)[0] == (mint)1);
        if(deg == -1)
            deg = this->size();
        if(deg == 0)
            return {};
        FPS t(begin(*this), begin(*this) + min<int>(deg, ssize(*this)));
        FPS res = t.diff() * t.inv(deg - 1);
        res.resize(deg - 1);
        return res.integral();
    }
    FPS exp(int deg = -1) {
        assert(!this->empty() and (*this)[0] == (mint)0);
        if(deg == -1)
            deg = this->size();
        if(deg == 0)
            return {};
        FPS res = {1};
        FPS f;
        f.reserve(this->size());
        for(int d = 1; d < deg << 1; d <<= 1) {
            while(ssize(f) < min(ssize(*this), d))
                f.emplace_back((*this)[f.size()]);
            res *= (FPS({1}) + f - res.log(d));
            while(ssize(res) > min(d, deg))
                res.pop_back();
        }
        return res;
    }
};
#line 3 "poly/sum-of-powers.hpp"
/**
 * @brief 列の冪乗和
 * @see https://yukicoder.me/problems/no/1145/editorial
 */
/// 各i(0≦i≦k)についてsum[j]a_j^iを求め、長さk+1の列を返す
/// O(n*log(n)^2 + k*log(k))時間
template <class mint>
vector<mint> sum_of_powers(const vector<mint> &a, int k) {
    if(a.empty())
        return vector<mint>(k + 1, 0);
    queue<FormalPowerSeries<mint>> que;
    for(auto &ai : a)
        que.push({1, -ai});
    while(que.size() > 1) {
        auto f = que.front();
        que.pop();
        auto g = que.front();
        que.pop();
        que.push(f * g);
    }
    auto &f = que.front();
    f = f.log(k + 1);
    for(int i = 1; i <= k; ++i)
        f[i] = -f[i] * mint(i);
    f[0] = ssize(a);
    return f;
}
/// 各i(0≦i≦k)についてsum[j in (0,n]]j^iを求め、長さk+1の列を返す
/// O(n*log(n)^2 + k*log(k))時間 ←修正
template <class mint>
vector<mint> sum_of_powers_iota(int n, int k) {
    using FPS = FormalPowerSeries<mint>;
    FPS res = (FPS({0, n}).exp(k + 2) >> (1)) *
              (FPS({0, 1}).exp(k + 2) >> (1)).inv(k + 1);
    res.resize(k + 1);
    mint fac = 1;
    for(int i = 0; i <= k; ++i) {
        res[i] *= fac;
        fac *= i + 1;
    }
    debug(n, k, res);
    return res;
}
#line 5 "/home/y_midori/cp/test/test.test.cpp"
#include <atcoder/modint>
using mint = atcoder::modint998244353;
factorial<mint> fac;
void solve() {
    INT(h, w, n, k);
    mint ans = 0;
    int imax = min(k, h - k), jmax = min(k, w - k);
    mint linv = mint(mint(h - k + 1) * (w - k + 1)).inv();
    // 四隅
    ans += mint(4) * imax * jmax;
    // mint wi, wj;
    vector<mint> sh = sum_of_powers_iota<mint>(imax + 1, n),
                 sw = sum_of_powers_iota<mint>(jmax + 1, n);
    sh[0]--, sw[0]--;
    debug(imax, n, sh);
    for(int m = 0; m <= n; ++m) {
        ans -= 4 * fac.binom(n, m) * (-linv).pow(m) * sh[m] * sw[m];
    }
    mint hl = abs(h - 2 * k), wl = abs(w - 2 * k);
    mint hr = (h >= 2 * k ? k : h - k + 1), wr = (w >= 2 * k ? k : w - k + 1);
    // 中
    mint p = 1 - linv * hr * wr;
    ans += hl * wl * (1 - p.pow(n));
    // 上下左右
    ans += 2 * (wl * imax + hl * jmax);
    for(int m = 0; m <= n; ++m) {
        ans -= 2 * fac.binom(n, m) * (-linv).pow(m) *
               (hl * (hr.pow(m)) * sw[m] + wl * (wr.pow(m)) * sh[m]);
    }
    print(ans);
}
int main() { solve(); }