#include <bits/stdc++.h>
const int maxn = 1200000 + 10;
int a, b, c, n, m, Ans = 1;
int pr[maxn], tot; bool flag[maxn];
long long f[maxn], g[maxn], Delta;
std::unordered_map<long long, int> cnt;
inline long long add (long long x, long long y, long long mod) {return x + y >= mod ? x + y - mod : x + y;}
inline long long mul (long long x, long long y, long long mod) {return (__int128)x * y % mod;}
inline long long power (long long x, long long y, long long mod)
{
    long long z = 1; x %= mod;
    for (; y; y >>= 1, x = mul(x, x, mod)) if (y & 1) z = mul(z, x, mod);
    return z;
}
inline long long Rand (long long l, long long r)
{
    long long x = 0;
    for (int i = 0; i < 4; i++) x = (x << 15) | (rand() & 32767);
    return x % (r - l + 1) + l;
}
namespace Quadratic_Residue
{
    long long p, w, r;
    struct Complex {long long real, imag;} ;
    inline Complex operator * (const Complex &a, const Complex &b)
    {
        Complex c = (Complex){0, 0};
        c.real = add(mul(a.real, b.real, p), mul(mul(a.imag, b.imag, p), r, p), p);
        c.imag = add(mul(a.real, b.imag, p), mul(a.imag, b.real, p), p);
        return c;
    }
    inline Complex Power (Complex x, long long y)
    {
        Complex z = (Complex){1, 0};
        for (; y; y >>= 1, x = x * x) if (y & 1) z = z * x;
        return z;
    }
    inline long long L (long long n)
    {
        if (n == 0) return 0;
        return power(n, (p - 1) / 2, p);
    }
    inline void init (long long q) {p = q;}
    inline long long Sqrt (long long n)
    {
        if (n == 0) return 0;
        if (L(n) == p - 1) return -1;
        do w = Rand(0, p - 1), r = add(mul(w, w, p), p - n, p);
        while (L(r) != p - 1) ;
        return Power((Complex){w, 1}, (p + 1) / 2).real;
    }
}
inline void Divide (long long &x, long long p, int w)
{
    while (x % p == 0) x /= p, (w && cnt[p]++);
}
inline void solve (long long p)
{
    if (p == 2 or a % p == 0)
    {
        for (int j = 1; j <= n; j++) Divide(f[j], p, 1);
    }
    else
    {
        Quadratic_Residue::init(p);
        long long r = Quadratic_Residue::Sqrt((Delta % p + p) % p);
        if (~r)
        {
            long long inv = power(2 * a, p - 2, p);
            long long r1 = mul(p + p - b % p - r, inv, p);
            long long r2 = mul(p + p - b % p + r, inv, p);
            for (long long j = r1; j <= n; j += p) if (j) Divide(f[j], p, 1);
            for (long long j = r2; j <= n; j += p) if (j) Divide(f[j], p, 1);
        }
    }
}
signed main ()
{
    scanf("%d%d%d%d", &a, &b, &c, &n);
    for (int i = 1; i <= n; i++) f[i] = 1LL * a * i * i + 1LL * b * i + c;
    for (int i = 1; i <= 2 * n; i++) g[i] = 1LL * a * i + b;
    m = std::max(2 * n, (int)std::max(pow(f[n], 1.0 / 3), sqrt(g[2 * n])));
    for (int i = 2; i <= m; i++)
    {
        if (!flag[i]) pr[++tot] = i;
        for (int j = 1; j <= tot and i * pr[j] <= m; j++)
        {
            flag[i * pr[j]] = true;
            if (i % pr[j] == 0) break;
        }
    }
    Delta = 1LL * b * b - 4LL * a * c;
    for (int i = 1; i <= tot; i++)
    {
        int p = pr[i]; solve(p);
        if (a % p == 0 or b % p == 0)
        {
            for (int j = 1; j <= 2 * n; j++) Divide(g[j], p, 0);
        }
        else
        {
            int r = 1LL * (p - b % p) * power(a, p - 2, p) % p;
            for (int j = r; j <= 2 * n; j += p) if (j) Divide(g[j], p, 0);
        }
    }
    g[0] = 1; std::sort(g + 1, g + 2 * n + 1);
    for (int i = 1; i <= 2 * n; i++) if (g[i] > g[i - 1]) solve(g[i]);
    for (int i = 1; i <= n; i++) if (f[i] > 1)
    {
        long long x = sqrt(f[i]);
        if (x * x == f[i]) cnt[x] += 2;
    }
    for (auto p: cnt) Ans = 1LL * Ans * power(p.first, p.second / 2 * 2, 998244353) % 998244353;
    return !printf("%d\n", Ans);
}