reg D 2

#include <iostream>
#include <cmath>
#include <vector>
#include <queue>
#include <algorithm>
#include <string>
#include <stack>
#include <set>
#include <map>
#define pii pair <int, int>
#define pb(x) push_back(x)
using namespace std;
using ll = long long;
using ld = long double;
using db = double;
void cv(vector <int> &v) {
    for (auto x : v) cout << x << ' ';
    cout << "\n";
}

void cvl(vector <ll> &v) {
    for (auto x : v) cout << x << ' ';
    cout << "\n";
}


void cvv(vector <vector <int> > &v) {
    for (auto x : v) cv(x);
    cout << "\n";
}

void cvb(vector <bool> v) {
    for (bool x : v) cout << x << ' ';
    cout << "\n";
}

void cvs(vector <string>  v) {
    for (auto a : v) {
        cout << a << "\n";
    }
}

void cvp(vector <pii> a) {
    for (auto p : a) {
        cout << p.first << ' ' << p.second << "\n";
    }
    cout << "\n";
}

ll N, M, K, F;
ll mod = 998244353;

bool sh = 0;

string to2(int x) {
    string r = "";
    while (x > 0) {
        r += x % 2 + '0';
        x /= 2;
    }
    reverse(r.begin(), r.end());
    while (r.size() < N * M) {
        r = '0' + r;
    }
    return r;
}

// 0 = wh, 1 = bl
bool ok(vector <vector <int> > a) {
    int without = 0;
    if (sh) {
        //cout << "N M = " << N << ' ' << M << "\n";
    }
    for (int j = 0; j < N; ++j) {
        if (sh) {
            //cout << "j = " << j << "\n";
        }
        int row = 0;
        bool isrow = 0;
        for (int i = 0; i < M; ++i) {
            if (sh) {
                //cout << "i = " << i << ' ' ;
            }
            if (a[i][j] == 1) {
                row++;
                if (row == F) {
                    isrow = 1;
                    break;
                }
            } else {
                row = 0;
            }
        }

        if (isrow) {
            without = 0;
        } else {
            without++;
        }
        /*if (sh) {
            cout << "\n";
            cout << "isrow = " << isrow << "\n";
            cout << "row = " << row << "\n";
        }*/
        if (without == K) {
            return 0;
        }
    }
    return 1;
}

ll slv1() {
    ll ans = 0;
    vector <vector <int> > a(M, vector <int> (N));
    set <string> als;
    //set <vector <vector <int> > alv;
    for (int it = 0; it < pow(2, N * M); ++it) {
        string s = to2(it);
        als.insert(s);
        if (sh) {
            //cout << "it s = \n" << it << ' ' << s << "\n";
        }
        int id = -1;
        for (int i = 0; i < M; ++i) {
            for (int j = 0; j < N; ++j) {
                id++;
                if (s[id] == '0') {
                    a[i][j] = 0;
                } else {
                    a[i][j] = 1;
                }
            }
        }
        //alv.insert(a);


        bool gd = ok(a);
        if (gd) {
            if (sh) {
                //cout << "good\n";
            }
            ans++;
            ans %= mod;
        } else if (sh) {
            cout << "bad\n";
        }
        if (!gd) {
            continue;
        }
        if (sh) {
            cout << "a\n";
            cvv(a);
        }

        if (sh) {
            cout << "\n\n";
        }
    }
    if (sh) {
        cout << "als.size() = " << als.size() << "\n";
        //cout << "alv.size() = " << alv.size() << "\n";
    }
    return ans;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> M >> N >> K >> F;
    ll ans = -1;
    if (N * M <= 20) {
        ans = slv1();
    }
    cout << ans << "\n";
}