#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using namespace atcoder; typedef long long ll; #define rep(i, n) for (int i = 0; i < (int)(n); i++) #define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--) #define repk(i, k, n) for (int i = k; i < (int)(n); i++) #define all(v) v.begin(), v.end() #define mod1 1000000007 #define mod2 998244353 #define mod3 100000007 #define vi vector #define vs vector #define vc vector #define vl vector #define vb vector #define vvi vector> #define vvc vector> #define vvl vector> #define vvb vector> #define vvvi vector>> #define vvvl vector>> #define pii pair #define pil pair #define pli pair #define pll pair #define vpii vector> #define vpll vector> #define vvpii vector>> #define vvpll vector>> // using mint = modint998244353; template void debug(T e) { cerr << e << endl; } template void debug(vector &v) { rep(i, v.size()) { cerr << v[i] << " "; } cerr << endl; } template void debug(vector> &v) { rep(i, v.size()) { rep(j, v[i].size()) { cerr << v[i][j] << " "; } cerr << endl; } } template void debug(vector> &v) { rep(i, v.size()) { cerr << v[i].first << " " << v[i].second << endl; } } template void debug(set &st) { for (auto itr = st.begin(); itr != st.end(); itr++) { cerr << *itr << " "; } cerr << endl; } template void debug(multiset &ms) { for (auto itr = ms.begin(); itr != ms.end(); itr++) { cerr << *itr << " "; } cerr << endl; } template void debug(map &mp) { for (auto itr = mp.begin(); itr != mp.end(); itr++) { cerr << itr->first << " " << itr->second << endl; } } void debug_out() { cerr << endl; } template void debug_out(Head H, Tail... T) { cerr << H << " "; debug_out(T...); } using mint = modint998244353; void debug_mint1(vector &vec) { for (int i = 0; i < vec.size(); i++) { cerr << vec[i].val() << " "; } cerr << endl; } void debug_mint2(vector> &vec) { for (int i = 0; i < vec.size(); i++) { for (int j = 0; j < vec[i].size(); j++) { cerr << vec[i][j].val() << " "; } cerr << endl; } } int main() { ll N, K, X, Y; cin >> N >> K >> X >> Y; vector A(N); for (ll i = 0; i < N; i++) { cin >> A[i]; } ll INF = N * N + 100000; vector> dp(K, vector(K, -INF)); dp[X % K][Y % K] = 0; dp[Y % K][X % K] = 0; vector dp_max_r(K, -INF); vector dp_max_c(K, -INF); dp_max_r[X % K] = 0; dp_max_r[Y % K] = 0; dp_max_c[X % K] = 0; dp_max_c[Y % K] = 0; for (ll i = 0; i < N; i++) { // ここでの遷移を限定したものにできる ll rem = A[i] % K; // debug_out(i, rem); vector naname(K, -INF); for (ll j = 0; j < K; j++) { naname[j] = max(naname[j], dp[j][(2 * K - j - rem) % K] + 1); naname[(2 * K - j - rem) % K] = max(naname[(2 * K - j - rem) % K], dp[(2 * K - j - rem) % K][j] + 1); } for (ll j = 0; j < K; j++) { dp_max_r[j] = max(dp_max_r[j], dp[j][(2 * K - j - rem) % K] + 1); dp_max_c[j] = max(dp_max_c[j], dp[(2 * K - j - rem) % K][j] + 1); } for (ll j = 0; j < K; j++) { dp[j][rem] = max(dp[j][rem], dp_max_r[j]); dp[rem][j] = max(dp[rem][j], dp_max_c[j]); } for (ll j = 0; j < K; j++) { dp[j][(2 * K - j - rem) % K] = max(dp[j][(2 * K - j - rem) % K], naname[j]); dp_max_r[j] = max(dp_max_r[j], dp[j][(2 * K - j - rem) % K]); dp_max_c[(2 * K - j - rem) % K] = max( dp_max_c[(2 * K - j - rem) % K], dp[j][(2 * K - j - rem) % K]); } for (ll j = 0; j < K; j++) { dp_max_r[j] = max(dp_max_r[j], dp[j][rem]); dp_max_c[j] = max(dp_max_c[j], dp[rem][j]); dp_max_r[rem] = max(dp_max_r[rem], dp[j][rem]); dp_max_c[rem] = max(dp_max_c[rem], dp[rem][j]); } // debug(dp); // debug(dp_max_r); // debug(dp_max_c); } ll ans = 0; for (ll i = 0; i < K; i++) { for (ll j = 0; j < K; j++) { ans = max(ans, dp[i][j]); } } cout << ans << endl; }