import sys, math
def solve():
    data = sys.stdin.read().split()
    n = int(data[0])
    k = int(data[1])
    a = [int(x) for x in data[2:2+n]]
    grp_sum = [0] * k
    grp_cnt = [0] * k
    best = -10**9
    def dfs(i, max_g):
        nonlocal best
        if i == n:
            if max_g == k - 1:
                mx = -10**9
                mn = 10**9
                for g in range(k):
                    s, c = grp_sum[g], grp_cnt[g]
                    if c == 0:
                        return
                    avg = s / c
                    if avg > mx:
                        mx = avg
                    if avg < mn:
                        mn = avg
                diff = math.ceil(mx - mn)
                if diff > best:
                    best = diff
            return
        for g in range(max_g + 1):
            grp_sum[g] += a[i]
            grp_cnt[g] += 1
            dfs(i + 1, max_g)
            grp_sum[g] -= a[i]
            grp_cnt[g] -= 1
        if max_g + 1 < k:
            ng = max_g + 1
            grp_sum[ng] += a[i]
            grp_cnt[ng] += 1
            dfs(i + 1, ng)
            grp_sum[ng] -= a[i]
            grp_cnt[ng] -= 1
    dfs(0, -1)
    print(best)

if __name__ == '__main__':
    solve()