#include<bits/stdc++.h>
using namespace std;

// macro
#define rep(i, N) for(ll i = 0; i < (ll)(N); ++i)
#define per(i, N) for(ll i = (ll)(N) - 1; i >= 0; --i)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define bit(n, k) (((n) >> (k)) & 1)
#define pcnt(n) (bitset<64>(n).count())
#define endl '\n'
#define fi first
#define se second
#define mkpr make_pair
#define mktpl make_tuple
#define eb emplace_back

// input/output
template<class T> istream& operator>>(istream& is, vector<T>& V){
    for(auto& it : V) is >> it;
    return is;
}
template<class T> ostream& operator<<(ostream& os, vector<T>& V){
    for(int i = 0; i < (int)V.size(); i++){
        os << V[i];
        os << (i + 1 != (int)V.size() ? " " : "");
    }
    return os;
}
template<class T1, class T2> istream& operator>>(istream& is, pair<T1, T2>& P){
    is >> P.first >> P.second;
    return is;
}
template<class T1, class T2> ostream& operator<<(ostream& os, pair<T1, T2> P){
    os << P.first << " " << P.second << "";
    return os;
}

// setup
void set_fast_ios(size_t precision){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(precision);
    cerr << fixed << setprecision(precision);
}

// make_vector
template <class T>
vector<T> make_vector(size_t a, T b) {
    return vector<T>(a, b);
}
template <class... Ts>
auto make_vector(size_t a, Ts... ts) {
    return vector<decltype(make_vector(ts...))>(a, make_vector(ts...));
}

// debug
#ifdef LOCAL
#define debug(x) cerr << "line"<< __LINE__ << ": " << #x << " = " << x << '\n'
#define debugln() cerr << "line" << __LINE__ << ": passed.\n"
#else
#define debug(x, ...) void(0)
#define debugln() void(0)
#endif

// type
using ll = long long;
using ull = unsigned long long;
using ld = double;
using i128 = __int128_t;
using State = string::iterator;
using Pair = pair<ll, ll>;
using Tuple = tuple<ll, ll, ll>;
template<class T> using max_heap = priority_queue<T>;
template<class T> using min_heap = priority_queue<T, vector<T>, greater<T>>;
template<class T> using vec = vector<T>;
template<class T> using vvec = vec<vec<T>>;
template<class T> using vvvec = vec<vvec<T>>;

// constant
constexpr ll INF = 1001001001;
constexpr ll LINF = 1001001001001001001ll;
constexpr ll MOD998 = 998244353;
constexpr ll MOD107 = (ll)(1e9+7);
constexpr ll NIL = -1;
constexpr ll pm[2] = {1, -1};
constexpr ll dy[4] = {0, 1, 0, -1};
constexpr ll dx[4] = {1, 0, -1, 0};
constexpr ll dy8[8] = {0, 1, 1, 1, 0, -1, -1, -1};
constexpr ll dx8[8] = {1, 1, 0, -1, -1, -1, 0, 1};

// function
ll Gcd(ll a, ll b){ return b ? Gcd(b, a % b) : abs(a);}
ll Lcm(ll a, ll b){ return a / Gcd(a, b) * b;}
template<class T> T powi(T x, ll exp){
    return exp > 0 ? (exp & 1 ? x : 1) * powi(x * x, exp >> 1) : x / x;
}
ll modpow(ll x, ll exp, ll mod){
    x %= mod;
    return exp > 0 ? (exp & 1 ? x : 1) * modpow(x * x, exp >> 1, mod) % mod : 1;
}
template<class T> bool chmin(T &a, T b){ return a > b ? (a = b, true) : 0;}
template<class T> bool chmax(T &a, T b){ return a < b ? (a = b, true) : 0;}

// modint
template <int mod> struct modint{
    long long x;
    modint() : x(0) {}
    modint(long long _x){ x = _x % mod; if(x < 0) x += mod; }
    constexpr modint operator-() const { return modint(-x); }
    constexpr modint& operator+=(const modint& a){ if ((x += a.x) >= mod) x -= mod; return *this; }
    constexpr modint& operator-=(const modint& a){ if ((x += mod - a.x) >= mod) x -= mod; return *this; }
    constexpr modint& operator*=(const  modint& a){ (x *= a.x) %= mod; return *this; }
    constexpr modint& operator/=(const modint& a){ return (*this) *= a.mpow(mod-2); }
    constexpr modint operator+(const modint& a) const { return modint(*this) += a; }
    constexpr modint operator-(const modint& a) const { return modint(*this) -= a; }
    constexpr modint operator*(const modint& a) const { return modint(*this) *= a; }
    constexpr modint operator/(const modint& a) const { return modint(*this) /= a; }
    constexpr bool operator==(const modint& a) const { return (*this).x == a.x; }
    constexpr bool operator!=(const modint& a) const { return (*this).x != a.x; }
    constexpr const modint mpow(long long exp) const {
        modint res(1), x = *this;
        for(; exp; exp >>= 1){
            if(exp & 1) res *= x;
            x *= x;
        }
        return res;
    }
    friend istream& operator>>(istream& is, modint& m){ is >> m.x; m = modint<mod>(m.x); return is; }
    friend ostream& operator<<(ostream& os, const modint& m){ os << m.x; return os; }
    bool operator<(const modint& a) const { return (*this).x < a.x; }
};
constexpr ll MOD = MOD998;
using mint = modint<MOD>;

template<class T> struct Dijkstra{
    using DS = pair<T, int>;
    int N;
    T INFTY = 1001001001001001001ll;
    vector<T> dist;
    vector<int> prev;
    priority_queue<DS, vector<DS>, greater<DS>> Que;
    vector<vector<DS>> G;

    Dijkstra(int N) : N(N), G(N), dist(N), prev(N) {}
    void add_edge(int from, int to, T cst){
        G[from].emplace_back(DS{cst, to});
    }
    void solve(int s){
        for(int i = 0; i < N; i++) dist[i] = INFTY, prev[i] = -1;
        dist[s] = 0, prev[s] = -1;
        Que.push(DS{0, s});
        while(!Que.empty()){
            DS p = Que.top();
            Que.pop();
            int u = p.second;
            if(dist[u] != p.first) continue;
            for(auto v : G[u]){
                if(dist[v.second] > dist[u] + v.first){
                    dist[v.second] = dist[u] + v.first;
                    prev[v.second] = u;
                    Que.push(DS{dist[v.second], v.second});
                }
            }
        }
    }
};

int main(){
    set_fast_ios(15);
    int N, K; cin >> N >> K;
    vec<ll> A(N); cin >> A;

    map<tuple<int, int, ll>, ll> mp;
    auto rec = [&](auto f, int n, int c, ll g) -> ll {
        if(n == N) return g;
        if(mp.find(mktpl(n, c, g)) != mp.end()){
            return mp[mktpl(n, c, g)];
        }

        ll res = 1;
        for(int i = 0; i <= K; i++){
            if(i + c > K) continue;
            chmax(res, f(f, n + 1, i + c, Gcd(g, A[n] + i)));
            if(A[n] - i > 0) chmax(res, f(f, n + 1, i + c, Gcd(g, A[n] - i)));
        }
        return mp[mktpl(n, c, g)] = res;
    };

    ll ans = 1;
    for(int i = -K; i <= K; i++){
        if(A[0] + i > 0) chmax(ans, rec(rec, 1, abs(i), A[0] + i));
    }
    cout << ans << endl;
}