#include <bits/stdc++.h>
// Author: Kazuki_Will_Win_VOI_8703
#define fi first
#define se second
#define pii pair<int, int>
#define int long long
#define all(a) a.begin(), a.end()
using namespace std;
const int mn = 2e2 + 5, inf = 1e18;
int n, w, a[mn], t[mn], dp[mn][mn][mn][2];
void solve(){
cin >> n >> w;
a[n + 1] = w;
for(int i = 1; i <= n; i++) cin >> a[i];
for(int i = 1; i <= n; i++) cin >> t[i];
fill(&dp[0][0][0][0], &dp[0][0][0][0] + mn * mn * mn * 2, inf);
int res = 0;
dp[0][n + 1][0][0] = dp[0][n + 1][0][1] = 0;
for(int i = 0; i <= n; i++){
for(int j = n + 1; j > i; j--){
for(int k = 0; k <= n; k++){
if(dp[i][j][k][0] < inf){
res = max(res, k);
int val = dp[i][j][k][0] + a[i + 1] - a[i];
// if(val < 0) cout << "lef " << i << ' ' << j << ' ' << k << ' ' << 0 << ' ' << val << '\n';
if(val <= t[i + 1]) dp[i + 1][j][k + 1][0] = min(dp[i + 1][j][k + 1][0], val);
else dp[i + 1][j][k][0] = min(dp[i + 1][j][k][0], val);
val = dp[i][j][k][0] + a[i] + w - a[j - 1];
// if(val < 0) cout << "lef " << i << ' ' << j << ' ' << k << ' ' << 1 << ' ' << val << '\n';
if(val <= t[j - 1]) dp[i][j - 1][k + 1][1] = min(dp[i][j - 1][k + 1][1], val);
else dp[i][j - 1][k][1] = min(dp[i][j - 1][k][1], val);
}
if(dp[i][j][k][1] < inf){
res = max(res, k);
int val = dp[i][j][k][1] + w - a[j] + a[i + 1];
// if(val < 0) cout << "rig " << i << ' ' << j << ' ' << k << ' ' << 0 << ' ' << val << '\n';
if(val <= t[i + 1]) dp[i + 1][j][k + 1][0] = min(dp[i + 1][j][k + 1][0], val);
else dp[i + 1][j][k][0] = min(dp[i + 1][j][k][0], val);
val = dp[i][j][k][1] + a[j] - a[j - 1];
// if(val < 0) cout << "rig " << i << ' ' << j << ' ' << k << ' ' << 1 << ' ' << val << '\n';
if(val <= t[j - 1]) dp[i][j - 1][k + 1][1] = min(dp[i][j - 1][k + 1][1], val);
else dp[i][j - 1][k][1] = min(dp[i][j - 1][k][1], val);
}
}
}
}
cout << res << '\n';
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int t = 1;
// cin >> t;
while(t--) solve();
}
