n = int(input())
A = list(map(int, input().split()))
s = sum(A)
ans = 10**18
for k in range(1, 101):
    if k**2 > s:
        break
    B = list(range(1, k))+list(range(k, 0, -1))
    #print(B)
    m = len(B)
    temp = 0
    if m >= n:
        for i in range(m):
            if 0 <= i < n:
                if A[i] < B[i]:
                    temp += B[i]-A[i]
            else:
                temp += B[i]
        temp += s-sum(B)
    else:
        for i in range(n):
            if 0 <= i < m:
                if A[i] < B[i]:
                    temp += B[i]-A[i]
        temp += s-sum(B)
    #print(temp, B)
    ans = min(ans, temp)
print(ans)