// #pragma GCC target("avx2")
#pragma GCC optimize("O3", "unroll-loops")
// #include <bits/extc++.h>
// using namespace __gnu_pbds;
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define double long double
// template <typename T>
// using pbds_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
using pii = pair<int, int>;
template<typename T>
using prior = priority_queue<T, vector<T>, greater<T>>;
template<typename T>
using Prior = priority_queue<T>;
#define X first
#define Y second
#define ALL(x) (x).begin(), (x).end()
#define eb emplace_back
#define pb push_back
#define fastIO() ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define RANDOM() random_device __rd; \
mt19937 __gen = mt19937(__rd()); \
uniform_int_distribution<int> __dis(1, 1E8); \
auto rnd = bind(__dis, __gen)
const int INF = 1E18;
const int mod = 1E9 + 7;
int32_t main() {
fastIO();
int n, L;
cin >> n >> L;
vector<int> pl(n), t(n);
for (auto &x : pl) cin >> x;
for (auto &x : t) cin >> x;
int ans = 0;
for (int i = 0; i < (1<<n); ++i) {
int l = 0, r = n-1, _pl = 0, _t = 0, cnt = 0;
for (int j = 0; j < n; ++j) {
if (i >> j & 1) {
if ((_t += (L + pl[l] - _pl) % L) <= t[l]) ++cnt;
_pl = pl[l++];
}
else {
if ((_t += (L + _pl - pl[r]) % L) <= t[r]) ++cnt;
_pl = pl[r--];
}
}
ans = max(ans, cnt);
}
cout << ans << "\n";
return 0;
}
