#include <bits/stdc++.h>

using i64 = long long;
using u64 = unsigned long long;
using u32 = unsigned;
using u128 = unsigned __int128;
using i128 = __int128;

constexpr u32 P = 998244353;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int A, B, C;
    i64 N;
    std::cin >> A >> B >> C >> N;
    if (N == 1) {
        std::cout << A << "\n";
        return 0;
    }
    if (N == 2) {
        std::cout << B << "\n";
        return 0;
    }
    N -= 3;
    
    constexpr int m = 20;
    
    std::vector<i128> I;
    i128 period = 3 << (m - 1);
    
    std::vector<int> a(period);
    for (int i = 0; i < period; i++) {
        a[i] = (A ^ B) + C;
        if (a[i] >= (1 << m)) {
            a[i] -= (1 << m);
            if (i <= N) {
                I.push_back(i);
            }
        }
        A = B;
        B = a[i];
    }
    
    u32 ans = a[N % period];
    u32 pw = 1 << m;
    while (!I.empty()) {
        {
            int b = 0;
            for (auto i : I) {
                if (i % 3 == N % 3 || (i + 1) % 3 == N % 3) {
                    b ^= ((N - i) / period + 1) % 2;
                }
            }
            ans += b * pw;
            if (ans >= P) {
                ans -= P;
            }
            pw += pw;
            if (pw >= P) {
                pw -= P;
            }
        }
        
        std::vector<i128> nI;
        int z[3] {};
        for (auto i : I) {
            z[i % 3] ^= 1;
        }
        int x[3] {};
        for (auto i : I) {
            int y = x[i % 3] ^ x[(i + 2) % 3];
            if (y) {
                nI.push_back(i);
            }
            y ^= z[i % 3] ^ z[(i + 2) % 3];
            if (y) {
                nI.push_back(i + period);
            }
            x[i % 3] ^= 1;
        }
        I = std::move(nI);
        std::sort(I.begin(), I.end());
        while (!I.empty() && I.back() > N) {
            I.pop_back();
        }
        period *= 2;
    }
    
    std::cout << ans << "\n";
    
    return 0;
}