import sys

# sys.setrecursionlimit(1000005)
# sys.set_int_max_str_digits(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
# inf = -1-(-1 << 31)
inf = -1-(-1 << 63)
# md = 10**9+7
md = 998244353

n,k,x,y=LI()
aa=LI()

x%=k
y%=k
dp=[[-1]*k for _ in range(k)]
dp[x][y]=0
mx=[-1]*k
mx[x]=mx[y]=0

def update(i,j,v):
    if v>dp[i][j]:
        dp[i][j]=dp[j][i]=v
    if v>mx[i]:mx[i]=v
    if v>mx[j]:mx[j]=v

for a in aa:
    a%=k
    ijv=[]
    for i in range(k):
        if mx[i]!=-1:
            ijv.append((i,a,mx[i]))
        j=(-a-i)%k
        pre=dp[i][j]
        if pre!=-1:
            ijv.append((i,j,pre+1))
            ijv.append((i,a,pre+1))
            ijv.append((a,j,pre+1))
    for i,j,v in ijv:update(i,j,v)

print(max(mx))