n, h, hl = map(int, input().split())
cnt = f = [[0 for _ in range(1901)] for _ in range(1900)]
g = [0 for _ in range(1901)]
for ctr in range(n):
    lis = list(map(int, input().split()))
    for j in range(1, len(lis)):
        cnt[ctr][lis[j]] += 1
for ctr in range(n):
    f[ctr][h] = cnt[ctr][h]
    if f[ctr][h] > g[h]:
        g[h] = f[ctr][h]
for j in range(h - 1, -1, -1):
    for i in range(n):
        tmp = 0
        if j + hl <= h:
            if g[j + hl] > tmp: 
                tmp = g[j + hl]
        if f[i][j + 1] > tmp: 
            tmp = f[i][j + 1]
        f[i][j] = tmp + cnt[i][j]
        if f[i][j] > g[j]:
            g[j] = f[i][j]
ans = 0
for ctr in range(n):
    ans = max(ans, f[ctr][0])
print(ans)