# Aをソートして二分探索

N, K = map(int, input().split())
A = list(map(int, input().split()))
A.sort()

def check(x):
    last = A[0]
    count = 1
    s = 0
    for i in range(N):
        if A[i] > last + x:
            s += A[i-1]-last
            last = A[i]
            count += 1
    s += A[N-1]-last
    return count, s

#for x in range(25):
#    print(x, check(x))
#print()

OK1 = 10**12+1
NG1 = -1
while (OK1-NG1)>1:
    mid = (OK1+NG1)//2
    if check(mid)[0] <= K:
        OK1 = mid
    else: 
        NG1 = mid
#print(OK1)

OK2 = 10**12+1
NG2 = -1
while (OK2-NG2)>1:
    mid = (OK2+NG2)//2
    if check(mid)[0] <= K-1:
        OK2 = mid
    else: 
        NG2 = mid
#print(OK2)

ans = 10**12
for i in range(OK1, OK2+1):
    ans = min(ans, check(i)[1])
print(ans)