B = int(input())
N = int(input())
l = []

for i in range(N):
    l.append(int(input()))

n_median = 0
n_median1 = 0
if N % 2 == 0:
    n_median = N // 2 
    n_median1 = n_median - 1
else:
    n_median = (N -1) // 2

l.sort()
ck = l[n_median]
ck1 = l[n_median1]

ans = 0
ans1 = 0
for l_i in l:
    ans += abs(l_i - ck)
    ans1 += abs(l_i - ck1)

print(min(ans,ans1))