N=int(input())
A=list(map(int,input().split()))

A_sum=sum(A)
k=1
Ans=float("inf")
while k*k<=A_sum:
    B=list(range(1,k+1))
    B+=B[:-1][::-1]

    t=max(len(A),len(B))
    X=A+[0]*(t-len(A))
    Y=B+[0]*(t-len(B))

    p=q=0
    for i in range(len(A)):
        if X[i]<Y[i]:
            p+=Y[i]-X[i]
        else:
            q+=X[i]-Y[i]

    if q>=p:
        Ans=min(Ans,q)

    k+=1
print(Ans)