def solve():
    N=int(input())
    A=list(map(int,input().split()))
    A.sort()

    X=0
    for i in range(N):
        X+=(N-1-2*i)*A[i]

    A_max=max(A)
    T=[0]*(A_max+1)
    for a in A:
        T[a]=1

    for k in range(1,A_max+1):
        T[k]+=T[k-1]

    Y=0
    for k in range(1,A_max):
        if T[k]-T[k-1]==1:
            for p in range(1,A_max//k+1):
                left =max(1, p*k)
                right=min(A_max, (p+1)*k-1)

                Y+=k*p*(T[right]-T[left-1])
                if p==1:
                    Y-=k

    return X+Y

print(solve())