#include <bits/stdc++.h>
using namespace std;
template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl
using ll = long long;
const ll inf = 1e18;
const int maxn = 205;
ll n,l;
ll x[maxn], t[maxn];
ll dp[maxn][maxn][2][maxn]; // left end, right end, which end?, taken
// 0, 1,2,...,n
// n+1
ll f(int l, int r, int p, int taken) {
if (l<0 || l>n+1) return inf;
if (r<0 || r>n+1) return inf;
if (p<0) return inf;
ll &res = dp[l][r][p][taken];
if (~res) return res;
res = inf;
// don't take
if (p==0 && l>0) {
res = min(res, f(l-1,r,0,taken)+(x[l]-x[l-1]));
res = min(res, f(l-1,r,1,taken)+(x[n+1]-x[r])+x[l]);
}
if (p==1 && r<n+1) {
res = min(res, f(l,r+1,1,taken)+(x[r+1]-x[r]));
res = min(res, f(l,r+1,0,taken)+x[l]+(x[n+1]-x[r]));
}
// take
if (taken>0) {
ll tmp = -1;
if (p==0 && l>0) {
tmp = f(l-1,r,0,taken-1)+(x[l]-x[l-1]);
if (tmp<=t[l]) {
res = min(res, tmp);
}
tmp = f(l-1,r,1,taken-1)+(x[n+1]-x[r])+x[l];
if (tmp<=t[l]) {
res = min(res, tmp);
}
}
if (p==1 && r<n+1) {
tmp = f(l,r+1,1,taken-1)+(x[r+1]-x[r]);
if (tmp<=t[r]) {
res = min(res, tmp);
}
tmp = f(l,r+1,0,taken-1)+(x[n+1]-x[r])+x[l];
if (tmp<=t[r]) {
res = min(res, tmp);
}
}
}
return res;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin>>n>>l;
for (int i=1; i<=n; i++) {
cin>>x[i];
}
x[0] = 0;
x[n+1] = l;
for (int i=1; i<=n; i++) {
cin>>t[i];
}
int ans = 0;
memset(dp,-1,sizeof(dp));
dp[0][n+1][0][0] = 0;
dp[0][n+1][1][0] = 0;
for (int x=0; x<n+1; x++) {
for (int taken=1; taken<=n; taken++) {
if (f(x,x+1,0,taken)<inf) ans = max(ans, taken);
if (f(x,x+1,1,taken)<inf) ans = max(ans, taken);
}
}
cout<<ans<<endl;
return 0;
}
