n,k = map(int,input().split())
a = [int(i) for i in input().split()]

#a.sort(reverse=True)
#a = [13,11,17]
#print(a)
ans = k
val = 0
minv = min(a)

for i in range(n):
    tmp = ans % a[i]
    if tmp < minv:
        val = max(val,tmp)

print(val)