#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<vector>
#include<cmath>
#include<queue>
#include<stack>
#include<deque>
#include<map>
#include<set>
#define MAX(a,b) (a>b?a:b)
#define MIN(a,b) (a<b?a:b)
#define UP upper_bound
#define LB lower_bound
#define LL long long
#define Pi 3.14159265358
#define si size()
#define en end()
#define be begin()
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define ii set<int>::iterator
using namespace std;
void build(int ind, int L, int R)
{
     if(L==R)
      {
       tree[ind].st=0;
       tree[ind].en=0;
       tree[ind].mx=0;
       tree[ind].bl=1;
       return;
      }
     build(2*ind,L,(L+R)/2);
     build(2*ind+1,(L+R)/2+1,R);
     if(tree[2*ind].bl^tree[2*ind+1].bl){ tree[ind].bl=0; goto done; }
     else
      {
       int delta=min(C-tree[2*ind].mx,max(tree[2*ind+1].st-tree[2*ind].en+a[(R+L)/2+1]));
       if(max(C,tree[2*ind].en+delta)<tree[2*ind+1].st){ tree[ind].bl=0; goto done; }

      }
     done: ;
}
main(){
       cin>>n>>C;
       for(i=1;i<=n;i++)
        {
         scanf("%d",&a[i]);
         a[i+n]=a[i];
        }
       for(i=1;i<=n;i++)
        {
         scanf("%d",&b[i]);
         b[i+n]=b[i];
        }
       build(1,1,k);
       for(i=1;i<=n;i++)
        {
         l=i; r=n+i;
         Res=Solve(1,1,k);
         if(Res.bl)ans++;
        }
       cout<<ans;
       system("pause");
       }