b = int(input())
n = int(input())
a = [int(input()) for i in range(n)]
ans = 1e12
for i in range(n):
    top = a[i]
    diff = [a[j] - top for j in range(n)]
    diffabs = [abs(a[j] - top) for j in range(n)]
    if sum(diff) + b >= 0:
        ans = min(ans, sum(diffabs))
print(ans)