b=int(input())
n=int(input())
c=[int(input()) for i in range(n)]
c.sort()
ans=[]
if n//2==1:
  t=c[n//2]
  for i in range(max(t-10**5,0),t+10**5):
    ct=0
    y=b
    for j in range(n):
      if c[j]>=i:
        ct+=c[j]-i
        y+=c[j]-i
    for j in range(n):
      if c[j]<i:
        ct+=i-c[j]
        y-=i-c[j]
    if y>=0:
      ans.append(ct)
else:
  t1=c[n//2-1]
  t2=c[n//2]
  for i in range(max(t1-10**5,0),t1+10**5):
    ct=0
    y=b
    for j in range(n):
      if c[j]>=i:
        ct+=c[j]-i
        y+=c[j]-i
    for j in range(n):
      if c[j]<i:
        ct+=i-c[j]
        y-=i-c[j]
    if y>=0:
      ans.append(ct)
  for i in range(max(t2-10**5,0),t2+10**5):
    ct=0
    y=b
    for j in range(n):
      if c[j]>=i:
        ct+=c[j]-i
        y+=c[j]-i
    for j in range(n):
      if c[j]<i:
        ct+=i-c[j]
        y-=i-c[j]
    if y>=0:
      ans.append(ct)
print(min(ans))