#include <bits/stdc++.h> #define int long long using namespace std; const int N = 2e2 + 11; const int inf = 1e18 + 7; int x[N], t[N], n, L; signed main(){ ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); cin >> n >> L; for(int i = 1; i <= n; i++) cin >> x[i]; for(int i = 1; i <= n; i++) cin >> t[i]; x[n + 1] = L; vector < vector < vector < int > > > dp(n + 1, vector < vector < int > >(n + 1, vector < int >(2, inf))); int ans = 0; for(int k = 0; k <= n; k++){ vector < vector < vector < int > > > ndp(n + 1, vector < vector < int > >(n + 1, vector < int >(2, inf))); if(k == 0)[[unlikely]] ndp[0][0][0] = ndp[0][0][1] = 0; for(int i = 0; i <= n; i++){ for(int j = 0; j <= n - i; j++){ if(k == 0 && i == 0 && j == 0)[[unlikely]] continue; if(i > 0){ int T = dp[i - 1][j][0] + x[n - i + 2] - x[n - i + 1]; if(T <= t[n - i + 1]) ndp[i][j][0] = min(ndp[i][j][0], T); T = dp[i - 1][j][1] + x[j] + L - x[n - i + 1]; if(T <= t[n - i + 1]) ndp[i][j][0] = min(ndp[i][j][0], T); } if(j > 0){ int T = dp[i][j - 1][0] + L - x[n - i + 1] + x[j]; if(T <= t[j]) ndp[i][j][1] = min(ndp[i][j][1], T); T = dp[i][j - 1][1] + x[j] - x[j - 1]; if(T <= t[j]) ndp[i][j][1] = min(ndp[i][j][1], T); } if(i > 0) ndp[i][j][0] = min(ndp[i][j][0], ndp[i - 1][j][0] + x[n - i + 2] - x[n - i + 1]); if(i > 0) ndp[i][j][0] = min(ndp[i][j][0], ndp[i - 1][j][1] + x[j] + L - x[n - i + 1]); if(j > 0) ndp[i][j][1] = min(ndp[i][j][1], ndp[i][j - 1][0] + x[j] + L - x[n - i + 1]); if(j > 0) ndp[i][j][1] = min(ndp[i][j][1], ndp[i][j - 1][1] + x[j] - x[j - 1]); if(ndp[i][j][1] != inf || ndp[i][j][0] != inf) ans = k; } } dp = ndp; } cout << ans; } // subete no mono no owari wa sugu ni yattekuru