// Starcraft 2 enjoyer //
#include <bits/stdc++.h>
// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
using namespace std;
#define LSOne(X) ((X) & -(X))
const int N = 2e2 + 5;
const int K = 1e2 + 5;
const int M = 2e5 + 5;
const int LG = 20;
const long long INF = 1e18 + 5;
const int C = 26;
const int B = 1000;
const int MOD = 998244353;
int n, l, a[N], ans;
long long dp[2][N][N][N], t[N], dis[N][N];
inline void solve()
{
cin >> n >> l;
memset(dp, -1, sizeof(dp));
a[0] = 0;
for (int x = 1; x <= n; x++)
{
cin >> a[x];
}
t[0] = INF;
for (int x = 1; x <= n; x++)
{
cin >> t[x];
}
n++;
for (int x = 0; x < n; x++)
{
for (int y = 0; y < n; y++)
{
int z = y;
while (z != x)
{
int nxt = (z + 1) % n;
dis[x][y] += (a[nxt] - a[z] + l) % l;
z = nxt;
}
dis[x][y] = min(dis[x][y], l - dis[x][y]);
// cout << dis[x][y] << " " << x << " " << y << "\n";
}
}
dp[0][0][0][0] = 0;
dp[1][0][0][0] = 0;
for (int s = 0; s < n - 1; s++)
{
for (int r = s; r >= 0; r--)
{
int l = (r - s + n) % n;
for (int z = 0; z < n; z++)
{
if (dp[0][l][r][z] != -1) // at l
{
// cout << dp[l][r][z] << "|" << a[l] << " " << a[r] << "|" << z << "\n";
int nxt = (l - 1 + n) % n;
if (dis[l][nxt] + dp[0][l][r][z] <= t[nxt])
{
if (dp[0][nxt][r][z + 1] == -1 || dp[0][nxt][r][z + 1] > dis[l][nxt] + dp[0][l][r][z])
{
dp[0][nxt][r][z + 1] = dis[l][nxt] + dp[0][l][r][z];
}
}
else
{
if (dp[0][nxt][r][z] == -1 || dp[0][nxt][r][z] > dis[l][nxt] + dp[0][l][r][z])
{
dp[0][nxt][r][z] = dis[l][nxt] + dp[0][l][r][z];
}
}
nxt = (r + 1 + n) % n;
if (dis[l][nxt] + dp[0][l][r][z] <= t[nxt])
{
// cout << a[nxt] << " " << l << " " << z + 1 << "\n";
if (dp[1][l][nxt][z + 1] == -1 || dp[1][l][nxt][z + 1] > dis[l][nxt] + dp[0][l][r][z])
{
dp[1][l][nxt][z + 1] = dis[l][nxt] + dp[0][l][r][z];
}
}
else
{
if (dp[1][l][nxt][z] == -1 || dp[1][l][nxt][z] > dis[l][nxt] + dp[0][l][r][z])
{
dp[1][l][nxt][z] = dis[l][nxt] + dp[0][l][r][z];
}
}
}
if (dp[1][l][r][z] != -1) // at r
{
// cout << dp[l][r][z] << "|" << a[l] << " " << a[r] << "|" << z << "\n";
int nxt = (l - 1 + n) % n;
if (dis[r][nxt] + dp[1][l][r][z] <= t[nxt])
{
if (dp[0][nxt][r][z + 1] == -1 || dp[0][nxt][r][z + 1] > dis[r][nxt] + dp[1][l][r][z])
{
dp[0][nxt][r][z + 1] = dis[r][nxt] + dp[1][l][r][z];
}
}
else
{
if (dp[0][nxt][r][z] == -1 || dp[0][nxt][r][z] > dis[r][nxt] + dp[1][l][r][z])
{
dp[0][nxt][r][z] = dis[r][nxt] + dp[1][l][r][z];
}
}
nxt = (r + 1 + n) % n;
if (dis[r][nxt] + dp[1][l][r][z] <= t[nxt])
{
// cout << a[nxt] << " " << l << " " << z + 1 << "\n";
if (dp[1][l][nxt][z + 1] == -1 || dp[1][l][nxt][z + 1] > dis[r][nxt] + dp[1][l][r][z])
{
dp[1][l][nxt][z + 1] = dis[r][nxt] + dp[1][l][r][z];
}
}
else
{
if (dp[1][l][nxt][z] == -1 || dp[1][l][nxt][z] > dis[r][nxt] + dp[1][l][r][z])
{
dp[1][l][nxt][z] = dis[r][nxt] + dp[1][l][r][z];
}
}
}
}
}
}
for (int x = 0; x < n; x++)
{
for (int y = 0; y < n; y++)
{
for (int z = 0; z < n; z++)
{
if (dp[0][x][y][z] != -1)
ans = max(ans, z);
if (dp[1][x][y][z] != -1)
ans = max(ans, z);
}
}
}
cout << ans << "\n";
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin >> t;
for (int x = 1; x <= t; x++)
{
solve();
}
return 0;
}
