n = int(input())
a = list(map(int, input().split()))
s = []
m = 1

def f(m, a):
    s_tmp = 0
    for i in range(n):
        s_tmp = s_tmp + m % a[i]
    return s_tmp

for i in range(n):
    m = m * a[i]

for i in range(1,m):
    s.append(f(i, a))

print(max(s))