#include <bits/stdc++.h>
using namespace std;
const int MAXN = 100005;
const long long INF = 0x3f3f3f3f3f3f3f;
template <typename T>
inline void read(T &AKNOI) {
  T x = 0, flag = 1;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') flag = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  AKNOI = flag * x;
}
int n, k, w[MAXN], g[MAXN], stk[MAXN], top, ans;
long long A[MAXN], B[MAXN];
long long mnb[MAXN << 2], mnc[MAXN << 2], tag[MAXN << 2];
inline void puttag(int rt, long long tg) {
  mnc[rt] += tg;
  tag[rt] += tg;
}
inline void pushdown(int rt) {
  if (tag[rt]) {
    puttag((rt << 1), tag[rt]);
    puttag((rt << 1) | 1, tag[rt]);
    tag[rt] = 0;
  }
}
void Activate(int rt, int b, int e, int p) {
  if (b == e) {
    mnb[rt] = mnc[rt] = B[b];
    return;
  }
  int mid = (b + e) >> 1;
  pushdown(rt);
  if (p <= mid)
    Activate((rt << 1), b, mid, p);
  else
    Activate((rt << 1) | 1, mid + 1, e, p);
  mnb[rt] = min(mnb[(rt << 1)], mnb[(rt << 1) | 1]);
  mnc[rt] = min(mnc[(rt << 1)], mnc[(rt << 1) | 1]);
}
void Update(int rt, int b, int e, int l, int r, long long v) {
  if (l <= b && e <= r) {
    puttag(rt, v);
    return;
  }
  int mid = (b + e) >> 1;
  pushdown(rt);
  if (l <= mid) Update((rt << 1), b, mid, l, r, v);
  if (r > mid) Update((rt << 1) | 1, mid + 1, e, l, r, v);
  mnc[rt] = min(mnc[(rt << 1)], mnc[(rt << 1) | 1]);
}
int Query(int rt, int b, int e, int r, long long lmn) {
  if (b > r) return -1;
  if (b == e) return b;
  int mid = (b + e) >> 1;
  pushdown(rt);
  long long tmp = min(lmn, mnc[(rt << 1)]);
  if (r > mid && mnb[(rt << 1) | 1] - k <= tmp) {
    int ret = Query((rt << 1) | 1, mid + 1, e, r, tmp);
    if (~ret) return ret;
  }
  if (mnb[(rt << 1)] - k <= lmn) {
    return Query((rt << 1), b, mid, r, lmn);
  }
  return -1;
}
void init() {
  read(n);
  read(k);
  for (int i = 1; i < n; ++i) {
    read(w[i]);
  }
  for (int i = 1; i <= n; ++i) {
    read(g[i]);
    A[i] = A[i - 1] + g[i - 1] - w[i - 1];
    B[i] = B[i - 1] + w[i - 1] - g[i];
  }
}
void solve() {
  memset(mnb, 0x80, sizeof(mnb));
  memset(mnc, 0x3f, sizeof(mnc));
  A[n + 1] = -INF;
  stk[top = 0] = n + 1;
  for (int i = n; i >= 1; --i) {
    Activate(1, 1, n, i);
    while (top && A[stk[top]] >= A[i]) {
      if (top > 1) {
        Update(1, 1, n, stk[top - 1] - 1, n, A[stk[top]] - A[stk[top - 1]]);
      }
      --top;
    }
    stk[++top] = i;
    if (top > 1) {
      Update(1, 1, n, stk[top - 1] - 1, n, A[stk[top - 1]] - A[stk[top]]);
    }
    int l = 1, r = top, p;
    while (l <= r) {
      int m = (l + r) >> 1;
      if (A[i] - A[stk[m]] <= k) {
        p = r = m - 1;
      } else {
        l = m + 1;
      }
    }
    ans = max(ans, Query(1, 1, n, stk[p] - 1, INF) - i + 1);
  }
  printf("%d\n", ans);
}
int main() {
  init();
  solve();
  return 0;
}
