#ifndef CPL_TEMPLATE
#define CPL_TEMPLATE
/*
Normie's Template v2.5
Changes:
Added warning against using pragmas on USACO.
*/
// Standard library in one include.
#include <bits/stdc++.h>
using namespace std;
// ordered_set library.
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set(el) tree<el,null_type,less<el>,rb_tree_tag,tree_order_statistics_node_update>
// AtCoder library. (Comment out these two lines if you're not submitting in AtCoder.) (Or if you want to use it in other judges, run expander.py first.)
//#include <atcoder/all>
//using namespace atcoder;
//Pragmas (Comment out these three lines if you're submitting in szkopul or USACO.)
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast,unroll-loops,tree-vectorize")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
//File I/O.
#define FILE_IN "cseq.inp"
#define FILE_OUT "cseq.out"
#define ofile freopen(FILE_IN,"r",stdin);freopen(FILE_OUT,"w",stdout)
//Fast I/O.
#define fio ios::sync_with_stdio(0);cin.tie(0)
#define nfio cin.tie(0)
#define endl "\n"
//Order checking.
#define ord(a,b,c) ((a>=b)and(b>=c))
//min/max redefines, so i dont have to resolve annoying compile errors.
#define min(a,b) (((a)<(b))?(a):(b))
#define max(a,b) (((a)>(b))?(a):(b))
// Fast min/max assigns to use with AVX.
// Requires g++ 9.2.0.
template<typename T>
__attribute__((always_inline)) void chkmin(T& a, const T& b) {
a=(a<b)?a:b;
}
template<typename T>
__attribute__((always_inline)) void chkmax(T& a, const T& b) {
a=(a>b)?a:b;
}
//Constants.
#define MOD (ll(998244353))
#define MAX 300001
#define mag 320
const long double PI=3.14159265358979;
//Pairs and 3-pairs.
#define p1 first
#define p2 second.first
#define p3 second.second
#define fi first
#define se second
#define pii(element_type) pair<element_type,element_type>
#define piii(element_type) pair<element_type,pii(element_type)>
//Quick power of 2.
#define pow2(x) (ll(1)<<x)
//Short for-loops.
#define ff(i,__,___) for(int i=__;i<=___;i++)
#define rr(i,__,___) for(int i=__;i>=___;i--)
//Typedefs.
#define bi BigInt
typedef long long ll;
typedef long double ld;
typedef short sh;
// Binpow and stuff
ll BOW(ll a, ll x, ll p)
{
if (!x) return 1;
ll res=BOW(a,x/2,p);
res*=res;
res%=p;
if (x%2) res*=a;
return res%p;
}
ll INV(ll a, ll p)
{
return BOW(a,p-2,p);
}
//---------END-------//
#endif
vector<int> vec;
ll n,m,i,j,k,l,t,t1,u,v,a,b,res=0;
ll arr[202],brr[202];
ll dp[202][202][202][2];
int main()
{
fio;
cin>>n>>t;
for (i=1;i<=n;i++)
{
cin>>arr[i];
}
for (i=1;i<=n;i++)
{
cin>>brr[i];
}
if (n==1)
{
if (min(arr[1],t-arr[1])<=brr[1]) cout<<1;
else cout<<0;
return 0;
}
arr[0]=0;
arr[n+1]=t;
for (i=1;i<=n;i++) for (j=i;j<=n;j++)
for (k=0;k<=n-(j-i+1);k++)
{
dp[i][j][k][0]=1e18;
dp[i][j][k][1]=1e18;
}
if (arr[1]<=brr[1])
{
dp[2][n][1][0]=arr[1];
}
else
{
dp[2][n][0][0]=arr[1];
}
if (t-arr[n]<=brr[n])
{
dp[1][n-1][1][1]=t-arr[n];
}
else
{
dp[1][n-1][0][1]=t-arr[n];
}
for (i=1;i<=n;i++) for (j=n;j>=i;j--) for (k=0;k<=n-(j-i+1);k++)
{
if ((i==1)and(j==n)) continue;
if (dp[i][j][k][0]<1e17) res=max(res,k);
// if (dp[i][j][k][0]<1e18) cout<<i<<' '<<j<<' '<<k<<' '<<0<<" | "<<dp[i][j][k][0]<<endl;
// if (dp[i][j][k][1]<1e18) cout<<i<<' '<<j<<' '<<k<<' '<<1<<" | "<<dp[i][j][k][1]<<endl;
if (dp[i][j][k][1]<1e17) res=max(res,k);
if (i<j)
{
if (dp[i][j][k][0]<1e17)
{
u=dp[i][j][k][0]+(arr[i]-arr[i-1]);
if (u<=brr[i])
dp[i+1][j][k+1][0]=min(dp[i+1][j][k+1][0],u);
else
dp[i+1][j][k][0]=min(dp[i+1][j][k][0],u);
u=dp[i][j][k][0]+(arr[i-1]+t-arr[j]);
if (u<=brr[j])
dp[i][j-1][k+1][1]=min(dp[i][j-1][k+1][1],u);
else
dp[i][j-1][k][1]=min(dp[i][j-1][k][1],u);
}
if (dp[i][j][k][1]<1e17)
{
u=dp[i][j][k][1]+(arr[j+1]-arr[j]);
if (u<=brr[j])
dp[i][j-1][k+1][1]=min(dp[i][j-1][k+1][1],u);
else
dp[i][j-1][k][1]=min(dp[i][j-1][k][1],u);
u=dp[i][j][k][1]+(arr[i]+t-arr[j+1]);
if (u<=brr[i])
dp[i+1][j][k+1][0]=min(dp[i+1][j][k+1][0],u);
else
dp[i+1][j][k][0]=min(dp[i+1][j][k][0],u);
}
}
else
{
if((dp[i][j][k][0]+min(arr[i]-arr[i-1],t-(arr[i]-arr[i-1]))<=brr[i])
or (dp[i][j][k][1]+min(arr[i+1]-arr[i],t-(arr[i+1]-arr[i]))<=brr[i]))
res=max(res,k+1);
}
}
cout<<res;
}
// a
