#include <bits/stdc++.h>
#define int long long
using namespace std;
int memo[210][210][210][2];
int pos[210],reach[210];
int n,l;
int dp(int left,int right,int num,int side){
if (num < 0) return 1e18;
if (left == 0 && right == 0){
if (num == 0) return 0;
return 1e18;
}
if (memo[left][right][num][side] != -1) return memo[left][right][num][side];
if (side){
int mintime = 1e18;
if (right != 0){
int temp1 = min(dp(left,right-1,num-1,1)+pos[right]-pos[right-1],dp(left,right-1,num-1,0)+(pos[right]+l-pos[left])%l);
if (temp1 <= reach[right]) mintime = min(mintime,temp1);
int temp2 = min(dp(left,right-1,num,1)+pos[right]-pos[right-1],dp(left,right-1,num,0)+(pos[right]+l-pos[left])%l);
mintime = min(mintime,temp2);
}
//if (num == 6)cout << left << " " << right << " " << num << " " << side << " " << mintime << "\n";
return memo[left][right][num][side] = mintime;
}
else{
int mintime = 1e18;
if (left != 0){
int temp1 = min(dp((left+1)%n,right,num-1,1)+(pos[right]+l-pos[left])%l,dp((left+1)%n,right,num-1,0)+(pos[(left+1)%n]+l-pos[left])%l);
if (temp1 <= reach[left]) mintime = min(mintime,temp1);
int temp2 = min(dp((left+1)%n,right,num,1)+(pos[right]+l-pos[left])%l,dp((left+1)%n,right,num,0)+(pos[(left+1)%n]+l-pos[left])%l);
mintime = min(mintime,temp2);
}
//if (num == 6)cout << left << " " << right << " " << num << " " << side << " " << mintime << "\n";
return memo[left][right][num][side] = mintime;
}
}
main(){
cin >> n >> l;
for (int i = 0; i <= n; i++) for (int j = 0; j <= n; j++) for (int k = 0; k <= n; k++) memo[i][j][k][0] = memo[i][j][k][1] = -1;
for (int i = 1; i <= n; i++) cin >> pos[i];
for (int i = 1; i <= n; i++) cin >> reach[i];
n++;
pos[0] = 0;
reach[0] = 1e18;
dp(5,1,3,0);
int ans = 0;
for (int i = 1; i < n; i++){
for (int j = 0; j < n; j++){
for (int k = j+1; k <= n; k++){
//cout << j << " " << k%n << "hi\n";
if (min(dp(k%n,j,i,0),dp(k%n,j,i,1)) != 1e18) ans = i;
}
}
}
cout << ans;
}
