#include <bits/stdc++.h>
using namespace std;
namespace io {
const int SI = 1 << 21 | 1;
char IB[SI], *IS, *IT, OB[SI], *OS = OB, *OT = OS + SI - 1, c, ch[100];
int f, t;
inline void flush() { fwrite(OB, 1, OS - OB, stdout), OS = OB; }
inline void pc(char x) {
  *OS++ = x;
  if (OS == OT) flush();
}
template <class I>
inline void rd(I &x) {
  for (f = 1, c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                              IS == IT ? EOF : *IS++)
                            : *IS++);
       c < '0' || c > '9';
       c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                       IS == IT ? EOF : *IS++)
                     : *IS++))
    if (c == '-') f = -1;
  for (x = 0; c >= '0' && c <= '9'; x = (x << 3) + (x << 1) + (c & 15),
      c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                      IS == IT ? EOF : *IS++)
                    : *IS++))
    ;
  x *= f;
}
template <class I>
inline void rd(I &x, I &y) {
  rd(x), rd(y);
}
template <class I>
inline void rd(I &x, I &y, I &z) {
  rd(x), rd(y), rd(z);
}
template <class I>
inline void rda(I *a, int n) {
  for (int i = 1; i <= n; i++) rd(a[i]);
}
inline void rdc(char &c) {
  for (c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                       IS == IT ? EOF : *IS++)
                     : *IS++);
       c < 33 || c > 126;
       c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                       IS == IT ? EOF : *IS++)
                     : *IS++))
    ;
}
inline void rds(char *s, int &x) {
  for (c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                       IS == IT ? EOF : *IS++)
                     : *IS++);
       c < 33 || c > 126;
       c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                       IS == IT ? EOF : *IS++)
                     : *IS++))
    ;
  for (x = 0; c >= 33 && c <= 126;
       s[++x] = c, c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                                   IS == IT ? EOF : *IS++)
                                 : *IS++))
    ;
  s[x + 1] = '\0';
}
template <class I>
inline void print(I x, char k = '\n') {
  if (!x) pc('0');
  if (x < 0) pc('-'), x = -x;
  while (x) ch[++t] = x % 10 + '0', x /= 10;
  while (t) pc(ch[t--]);
  pc(k);
}
template <class I>
inline void print(I x, I y) {
  print(x, ' '), print(y);
}
template <class I>
inline void print(I x, I y, I z) {
  print(x, ' '), print(y, ' '), print(z);
}
inline void printc(char c) { pc(c); }
inline void prints(string s) {
  int x = s.length();
  while (t < x) pc(s[t++]);
  pc('\n'), t = 0;
}
struct Flush {
  ~Flush() { flush(); }
} flusher;
}  // namespace io
using io::print;
using io::printc;
using io::prints;
using io::rd;
using io::rda;
using io::rdc;
using io::rds;
const int N = 1e5 + 7;
const long long inf = 1e18;
int n, ans, s[N], p;
long long k, w[N], g[N], a[N], b[N], c[N], d[N];
struct T {
  int l, r;
  long long x, z, d;
} t[N << 2];
void build(int p, int l, int r) {
  t[p].l = l, t[p].r = r, t[p].x = -inf;
  if (t[p].l == t[p].r) return;
  build((p << 1), l, ((t[p].l + t[p].r) >> 1)),
      build(((p << 1) | 1), ((t[p].l + t[p].r) >> 1) + 1, r);
}
inline void upd(int p) {
  t[p].x = max(t[(p << 1)].x, t[((p << 1) | 1)].x);
  t[p].d = max(t[(p << 1)].d, t[((p << 1) | 1)].d);
}
inline void spd(int p) {
  if (t[p].z) {
    t[(p << 1)].x += t[p].z;
    t[(p << 1)].z += t[p].z;
    t[((p << 1) | 1)].x += t[p].z;
    t[((p << 1) | 1)].z += t[p].z;
    t[p].z = 0;
  }
}
void setx(int p, int x, long long k) {
  if (t[p].l == t[p].r) return t[p].x = t[p].d = k, void();
  spd(p);
  if (x <= ((t[p].l + t[p].r) >> 1))
    setx((p << 1), x, k);
  else
    setx(((p << 1) | 1), x, k);
  upd(p);
}
void add(int p, int l, int r, long long k) {
  if (t[p].l >= l && t[p].r <= r) return t[p].x += k, t[p].z += k, void();
  spd(p);
  if (l <= ((t[p].l + t[p].r) >> 1)) add((p << 1), l, r, k);
  if (r > ((t[p].l + t[p].r) >> 1)) add(((p << 1) | 1), l, r, k);
  upd(p);
}
int ask(int p, int l, int r, long long x) {
  if (t[p].l > r || t[p].d + k < x) return 0;
  if (t[p].l == t[p].r) return t[p].l;
  spd(p);
  if (((t[p].l + t[p].r) >> 1) < l) return ask(((p << 1) | 1), l, r, x);
  if (r <= ((t[p].l + t[p].r) >> 1)) return ask((p << 1), l, r, x);
  if (t[((p << 1) | 1)].d + k >= max(x, t[(p << 1)].x)) {
    int ret = ask(((p << 1) | 1), l, r, max(x, t[(p << 1)].x));
    if (ret) return ret;
  }
  return ask((p << 1), l, r, x);
}
int main() {
  rd(n), rd(k), rda(w, n - 1), rda(g, n);
  for (int i = 1; i < n; i++) a[i] = a[i - 1] + w[i];
  for (int i = 1; i <= n; i++) b[i] = b[i - 1] + g[i];
  for (int i = 1; i <= n; i++) c[i] = a[i - 1] - b[i - 1];
  for (int i = 1; i <= n; i++) d[i] = b[i] - a[i - 1];
  build(1, 1, n);
  for (int i = n; i; i--) {
    while (p && c[i] >= c[s[p]]) {
      if (p > 1) add(1, s[p - 1] - 1, n, c[s[p]] - c[s[p - 1]]);
      --p;
    }
    s[++p] = i, setx(1, i, d[i]);
    if (p > 1) add(1, s[p - 1] - 1, n, c[s[p - 1]] - c[i]);
    int l = 1, r = p;
    while (l < r) {
      int mid = (l + r) >> 1;
      if (c[s[mid]] - c[i] <= k)
        r = mid;
      else
        l = mid + 1;
    }
    r = r == 1 ? n : s[r - 1] - 1;
    ans = max(ans, ask(1, i, r, -inf) - i + 1);
  }
  print(ans);
  return 0;
}
