B = int(input())
N = int(input())
C = [int(input()) for _ in range(N)]
C.sort()
SUM = sum(C)

rui = [0]
for c in C:
    rui.append(rui[-1] + c)

ansl = []
for i in range(N):
    target = C[i]
    temochi = B

    # 左には i 個いる
    temochi -= target * i - rui[i]

    # 右には N - 1 - i 個いる
    temochi += (SUM - rui[i + 1]) - target * (N - i - 1)

    if temochi >= 0:
        ans = 0
        for i in range(N):
            c = C[i]
            ans += abs(c - target)
        ansl.append(ans)

print(min(ansl))