#include <bits/stdc++.h>
#define For(i, a, b) for(int (i)=(int)(a); (i)<(int)(b); ++(i))
#define rFor(i, a, b) for(int (i)=(int)(a)-1; (i)>=(int)(b); --(i))
#define rep(i, n) For((i), 0, (n))
#define rrep(i, n) rFor((i), (n), 0)
#define fi first
#define se second
using namespace std;
typedef long long lint;
typedef unsigned long long ulint;
typedef pair<int, int> pii;
typedef pair<lint, lint> pll;
template<class T> bool chmax(T &a, const T &b){if(a<b){a=b; return true;} return false;}
template<class T> bool chmin(T &a, const T &b){if(a>b){a=b; return true;} return false;}
template<class T> T div_floor(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>=0 ? a/b : (a+1)/b-1;
}
template<class T> T div_ceil(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>0 ? (a-1)/b+1 : a/b;
}

constexpr lint mod = 1e9+7;
constexpr lint INF = mod * mod;
constexpr int MAX = 200010;

int n, K, a[10], sum[10], cnt[10], ans;

void dfs(int cur){
    if(cur == n){
        rep(i, K)if(cnt[i] == 0) return;
        rep(i, K)For(j, i+1, K){
            int tmp = (abs(sum[i]*cnt[j] - sum[j]*cnt[i])+cnt[i]*cnt[j]-1) / (cnt[i]*cnt[j]);
            chmax(ans, tmp);
        }
        return;
    }
    rep(i, K){
        sum[i] += a[cur];
        ++cnt[i];
        dfs(cur+1);
        sum[i] -= a[cur];
        --cnt[i];
    }
}

int main(){
    scanf("%d%d", &n, &K);
    rep(i, n) scanf("%d", &a[i]);
    dfs(0);
    printf("%d\n", ans);
}