#include <bits/stdc++.h> #define int long long #define fi first #define se second #define mp make_pair #define Sz(x) (int)x.size() using namespace std; const int N = 205; const int inf = 1e18; int n, l, x[N], t[N], dp[2][N][N][N]; int dist(int a, int b) { if (a > b) swap(a, b); return min(b - a, l - b + a); } void solve() { cin >> n >> l; for (int i = 1; i <= n; i++) { cin >> x[i]; } for (int i = 1; i <= n; i++) { cin >> t[i]; } for (int i = 0; i <= n; i++) { for (int j = 0; j <= n - i; j++) { for (int k = 0; k <= n; k++) { dp[0][i][j][k] = dp[1][i][j][k] = inf; } } } dp[0][0][0][0] = dp[1][0][0][0] = 0; for (int k = 0; k <= n; k++) { for (int tp = 0; tp < 2; tp++) { for (int i = 0; i <= n; i++) { for (int j = 0; j <= n - i; j++) { if (dp[tp][i][j][k] == inf) continue; int time = dp[tp][i][j][k], pos, k2 = k; int time2 = time; if (tp == 0) { if (i == 0) pos = 0; else pos = x[i]; } else { if (j == 0) pos = 0; else pos = x[n - j + 1]; } int pos2 = pos; for (int i2 = i + 1; i2 + j <= n; i2++) { time += dist(pos, x[i2]); pos = x[i2]; if (time <= t[i2]) k2++; dp[0][i2][j][k2] = min(dp[0][i2][j][k2], time); } pos = pos2, k2 = k, time = time2; for (int j2 = j + 1; j2 + i <= n; j2++) { time += dist(pos, x[n - j2 + 1]); pos = x[n - j2 + 1]; if (time <= t[n - j2 + 1]) k2++; dp[1][i][j2][k2] = min(dp[1][i][j2][k2], time); } } } } } int ans = 0; for (int tp = 0; tp < 2; tp++) { for (int i = 0; i <= n; i++) { for (int j = 0; j <= n - i; j++) { for (int k = 0; k <= n; k++) { if (dp[tp][i][j][k] != inf) ans = max(ans, k); } } } } cout << ans; } signed main() { ios_base::sync_with_stdio(0); cin.tie(0); int tt = 1; // cin >> tt; while (tt--) { solve(); // cout << '\n'; } }