#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")

////////////////////////////////////////////////////////////////////////////////
template <unsigned M_> struct ModInt {
  static constexpr unsigned M = M_;
  unsigned x;
  constexpr ModInt() : x(0U) {}
  constexpr ModInt(unsigned x_) : x(x_ % M) {}
  constexpr ModInt(unsigned long long x_) : x(x_ % M) {}
  constexpr ModInt(int x_) : x(((x_ %= static_cast<int>(M)) < 0) ? (x_ + static_cast<int>(M)) : x_) {}
  constexpr ModInt(long long x_) : x(((x_ %= static_cast<long long>(M)) < 0) ? (x_ + static_cast<long long>(M)) : x_) {}
  ModInt &operator+=(const ModInt &a) { x = ((x += a.x) >= M) ? (x - M) : x; return *this; }
  ModInt &operator-=(const ModInt &a) { x = ((x -= a.x) >= M) ? (x + M) : x; return *this; }
  ModInt &operator*=(const ModInt &a) { x = (static_cast<unsigned long long>(x) * a.x) % M; return *this; }
  ModInt &operator/=(const ModInt &a) { return (*this *= a.inv()); }
  ModInt pow(long long e) const {
    if (e < 0) return inv().pow(-e);
    ModInt a = *this, b = 1U; for (; e; e >>= 1) { if (e & 1) b *= a; a *= a; } return b;
  }
  ModInt inv() const {
    unsigned a = M, b = x; int y = 0, z = 1;
    for (; b; ) { const unsigned q = a / b; const unsigned c = a - q * b; a = b; b = c; const int w = y - static_cast<int>(q) * z; y = z; z = w; }
    assert(a == 1U); return ModInt(y);
  }
  ModInt operator+() const { return *this; }
  ModInt operator-() const { ModInt a; a.x = x ? (M - x) : 0U; return a; }
  ModInt operator+(const ModInt &a) const { return (ModInt(*this) += a); }
  ModInt operator-(const ModInt &a) const { return (ModInt(*this) -= a); }
  ModInt operator*(const ModInt &a) const { return (ModInt(*this) *= a); }
  ModInt operator/(const ModInt &a) const { return (ModInt(*this) /= a); }
  template <class T> friend ModInt operator+(T a, const ModInt &b) { return (ModInt(a) += b); }
  template <class T> friend ModInt operator-(T a, const ModInt &b) { return (ModInt(a) -= b); }
  template <class T> friend ModInt operator*(T a, const ModInt &b) { return (ModInt(a) *= b); }
  template <class T> friend ModInt operator/(T a, const ModInt &b) { return (ModInt(a) /= b); }
  explicit operator bool() const { return x; }
  bool operator==(const ModInt &a) const { return (x == a.x); }
  bool operator!=(const ModInt &a) const { return (x != a.x); }
  friend std::ostream &operator<<(std::ostream &os, const ModInt &a) { return os << a.x; }
};
////////////////////////////////////////////////////////////////////////////////

constexpr unsigned MO = 998244353;
using Mint = ModInt<MO>;



Mint Q;
Mint QQ[1010];

Mint dp[1010][1010];

int D;
vector<Mint> C;
// x^e mod C
vector<Mint> power(int e) {
  if (e == 0) {
    vector<Mint> ret(D, 0);
    ret[0] = 1;
    return ret;
  } else if (e & 1) {
    auto ret = power(e - 1);
    ret.insert(ret.begin(), 0);
    for (int j = 1; j <= D; ++j) {
      ret[D - j] -= C[j] * ret[D];
    }
    ret.resize(D);
    return ret;
  } else {
    const auto res = power(e >> 1);
    vector<Mint> ret(2*D, 0);
    for (int i = 0; i < D; ++i) for (int j = 0; j < D; ++j) {
      ret[i + j] += res[i] * res[j];
    }
    for (int i = 2*D; --i >= D; ) {
      for (int j = 1; j <= D; ++j) {
        ret[i - j] -= C[j] * ret[i];
      }
    }
    ret.resize(D);
    return ret;
  }
}

Mint solve(int N, int K) {
  memset(dp, 0, sizeof(dp));
  for (int h = K; h >= 0; --h) {
    const int lim = h ? (K / h) : K;
    const int lim1 = K / (h + 1);
    dp[h][0] = 1;
    for (int n = 1; n <= lim; ++n) {
      for (int m = 1; m <= lim1 && m < n; ++m) {
        dp[h][n] += dp[h][n - m - 1] * QQ[m] * (1 - Q) * dp[h + 1][m];
      }
      if (n <= lim1) {
        dp[h][n] += dp[h][0] * QQ[n] * dp[h + 1][n];
      }
      dp[h][n] += dp[h][n - 1] * (1 - Q);
    }
  }
  D = K + 1;
  C.assign(D + 1, 0);
  for (int m = 1; m <= K; ++m) {
    C[m + 1] -= QQ[m] * (1 - Q) * dp[1][m];
  }
  C[1] -= (1 - Q);
  C[0] = 1;
  const auto res = power(N);
  Mint ans = 0;
  for (int i = 0; i < D; ++i) {
    ans += dp[0][i] * res[i];
  }
  return ans;
}

int main() {
  int N, K;
  Mint X, Y;
  for (; ~scanf("%d%d%u%u", &N, &K, &X.x, &Y.x); ) {
    Q = X / Y;
    QQ[0] = 1;
    for (int i = 1; i <= K; ++i) {
      QQ[i] = QQ[i - 1] * Q;
    }
    Mint ans = 0;
    ans += solve(N, K);
    ans -= solve(N, K - 1);
    printf("%u\n", ans.x);
  }
  return 0;
}