import sys
input=sys.stdin.readline
def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))
mod=10**9+7

def main():
    N,K=MI()
    A=LI()
    A.sort()
    
    L=[]
    for i in range(N):
       L.append(K%A[i])
       
    ans=0
    
    for i in range(N):
        if L[i]<A[0]:
            ans=L[i]
            
    print(ans)
    
    
    


main()