#include <bits/stdc++.h>
using namespace std;
const long long maxn = 200 + 12, inf = 1e17 + 12;
long long n, L, dist[maxn], t[maxn], dp[maxn][maxn][maxn];
long long find_ans(int a, int b, int c, int k = 0){
if(c < 0)
return inf;
if(dp[a][b][c] != -1){
if(a != 0 && b != 0)
return dp[a][b][c] ;
if(a == 0 && b == 0)
return dp[a][b][c];
if(a == 0)
return dp[a][b][c] + k * (dist[b]);
return dp[a][b][c] + k * (L - dist[a]);
}
// cout << a << ' ' << b << ' ' << c << endl;
dp[a][b][c] = inf;
if(a == 0 && b == 0)
return dp[a][b][c];
if(a == 0){
dp[a][b][c] = min(dp[a][b][c], find_ans(a, b - 1, c) + abs(dist[b] - dist[b - 1]));
long long x = find_ans(a, b - 1, c - 1) + abs(dist[b] - dist[b - 1]);
if(x <= t[b])
dp[a][b][c] = min(dp[a][b][c], x);
// cout << a << ' ' << b << ' ' << c << ' ' << dp[a][b][c] << ' ' << k << endl;
return dp[a][b][c] + k * (dist[b]);
}
if(b == 0){
dp[a][b][c] = min(dp[a][b][c], find_ans((a + 1) % n, b, c) + (a + 1 == n? L - dist[a]: abs(dist[a] - dist[a + 1])));
long long x = find_ans((a + 1) % n, b, c - 1) + (a + 1 == n? L - dist[a]: abs(dist[a] - dist[a + 1]));
if(x <= t[a])
dp[a][b][c] = min(dp[a][b][c], x);
// cout << a << ' ' << b << ' ' << c << ' ' << dp[a][b][c] << ' ' << k << endl;
return dp[a][b][c] + k * (L - dist[a]);
}
if(a < b){
if(a != 1){
dp[a][b][c] = min(dp[a][b][c], find_ans(a - 1, b, c) + abs(dist[a] - dist[a - 1]));
long long x = find_ans(a - 1, b, c - 1) + abs(dist[a] - dist[a - 1]);
if(x <= t[a])
dp[a][b][c] = min(dp[a][b][c], x);
}
else{
dp[a][b][c] = min(dp[a][b][c], find_ans(b, a - 1, c, 1) + abs(dist[a] - dist[a - 1]));
long long x = find_ans(b, a - 1, c - 1, 1) + abs(dist[a] - dist[a - 1]);
if(x <= t[a])
dp[a][b][c] = min(dp[a][b][c], x);
}
dp[a][b][c] = min(dp[a][b][c], find_ans(b, a - 1, c) + abs(L - dist[b]) + dist[a]);
long long x = find_ans(b, a - 1, c - 1) + abs(L - dist[b]) + dist[a];
if(x <= t[a])
dp[a][b][c] = min(dp[a][b][c], x);
}
else if(a > b){
dp[a][b][c] = min(dp[a][b][c], find_ans((a + 1) % n, b, c, (a + 1 == n)) + (a + 1 == n? L - dist[a]: abs(dist[(a + 1) % n] - dist[a])));
long long x = find_ans((a + 1) % n, b, c - 1, (a + 1 == n)) + (a + 1 == n? L - dist[a]: abs(dist[(a + 1) % n] - dist[a]));
if(x <= t[a])
dp[a][b][c] = min(dp[a][b][c], x);
if(a + 1 != n){
dp[a][b][c] = min(dp[a][b][c], find_ans(b, (a + 1) % n, c) + dist[b] + abs(L - dist[a]));
long long x = find_ans(b, (a + 1) % n, c - 1) + dist[b] + abs(L - dist[a]);
if(x <= t[a])
dp[a][b][c] = min(dp[a][b][c], x);
}
else{
dp[a][b][c] = min(dp[a][b][c], find_ans((a + 1) % n, b, c) + dist[b] + abs(L - dist[a]));
long long x = find_ans((a + 1) % n, b, c - 1) + dist[b] + abs(L - dist[a]);
if(x <= t[a])
dp[a][b][c] = min(dp[a][b][c], x);
}
}
// cout << 'd' << ' ' << a << ' ' << b << ' ' << c << endl;
// if(dp[a][b][c] != inf)
// cout << a << ' ' << b << ' ' << c << ' ' << dp[a][b][c] << endl << endl;
return dp[a][b][c];
}
int main(){
ios_base::sync_with_stdio(false), cin.tie(0);
memset(dp, -1, sizeof dp);
cin >> n >> L;
for(int i = 1; i <= n; i++)
cin >> dist[i];
for(int i = 1; i <= n; i++)
cin >> t[i];
dist[0] = 0;
t[0] = 0;
n += 1;
dp[0][0][1] = 0;
dp[0][0][0] = 0;
int ans = 0;
// cout << find_ans(1, 5, 3) << endl;
// return 0;
for(int i = 0; i <= n; i++)
for(int j = 0; j <= n; j++)
for(int c = 0; c <= n; c++){
dp[i][j][c] = find_ans(i, j, c);
if(dp[i][j][c] != inf)
ans = max(ans, c);
}
cout << ans - 1 << endl;
}
