# medianにすればいいか

B = int(input())
N = int(input())
C = []
for i in range(N):
    C.append(int(input()))
C.sort()

C_cumu = [0]
temp = 0
for i in range(N):
    temp += C[i]
    C_cumu.append(temp)
    
from math import floor, ceil
if N%2 == 1:
    median = C[N//2]
    ans = 0
    ans += median*(N//2) - C_cumu[N//2]
    ans += C_cumu[N] - C_cumu[N//2+1] - median*(N//2)
    #print(median, ans)
else:
    median_low = floor((C[N//2-1]+C[N//2])/2)
    ans_low = 0
    ans_low += median_low*(N//2) - C_cumu[N//2]
    ans_low += C_cumu[N] - C_cumu[N//2] - median_low*(N//2)
    #print(median_low, ans_low)
    median_high = ceil((C[N//2-1]+C[N//2])/2)
    ans_high = 0
    ans_high += median_high*(N//2) -C_cumu[N//2]
    ans_high += C_cumu[N] - C_cumu[N//2] - median_high*(N//2)
    #print(median_high, ans_high)
    ans = min(ans_low, ans_high)
print(ans)