#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
inline void smin(T &a, U b) {
  if (a > b) a = b;
}
template <typename T, typename U>
inline void smax(T &a, U b) {
  if (a < b) a = b;
}
template <class T>
inline void gn(T &first) {
  char c, sg = 0;
  while (c = getchar(), (c > '9' || c < '0') && c != '-')
    ;
  for ((c == '-' ? sg = 1, c = getchar() : 0), first = 0; c >= '0' && c <= '9';
       c = getchar())
    first = (first << 1) + (first << 3) + c - '0';
  if (sg) first = -first;
}
template <class T, class T1>
inline void gn(T &first, T1 &second) {
  gn(first);
  gn(second);
}
template <class T, class T1, class T2>
inline void gn(T &first, T1 &second, T2 &z) {
  gn(first);
  gn(second);
  gn(z);
}
template <class T>
inline void print(T first) {
  if (first < 0) {
    putchar('-');
    return print(-first);
  }
  if (first < 10) {
    putchar('0' + first);
    return;
  }
  print(first / 10);
  putchar(first % 10 + '0');
}
template <class T>
inline void printsp(T first) {
  print(first);
  putchar(' ');
}
template <class T>
inline void println(T first) {
  print(first);
  putchar('\n');
}
template <class T, class U>
inline void print(T first, U second) {
  printsp(first);
  println(second);
}
template <class T, class U, class V>
inline void print(T first, U second, V z) {
  printsp(first);
  printsp(second);
  println(z);
}
int power(int a, int b, int m, int ans = 1) {
  for (; b; b >>= 1, a = 1LL * a * a % m)
    if (b & 1) ans = 1LL * ans * a % m;
  return ans;
}
const long long MM = 1231231;
int val[202020 << 2], cnt[202020 << 2];
int a[202020], f[202020];
pair<int, int> p[202020];
void update(int u, int L, int R, int r, int c) {
  if (L > r || R <= r) return;
  if (L + 1 == R) {
    val[u] += c;
    if (val[u])
      cnt[u] = 1;
    else
      cnt[u] = 0;
    return;
  }
  update((u << 1), L, (L + R >> 1), r, c);
  update(((u << 1) | 1), (L + R >> 1), R, r, c);
  cnt[u] = cnt[(u << 1)] + cnt[((u << 1) | 1)];
  val[u] = ((long long)val[(u << 1)] * f[cnt[((u << 1) | 1)]] +
            val[((u << 1) | 1)]) %
           1000000007;
}
int main() {
  int n, m;
  gn(n, m);
  for (int i = 1; i <= n; i++) gn(a[i]);
  for (int j = 1; j <= m; j++) gn(p[j].first), p[j].second = j;
  sort(p + 1, p + m + 1);
  for (int i = f[0] = 1; i <= m; i++)
    f[i] = (long long)f[i - 1] * MM % 1000000007;
  for (int i = 1; i <= n; i++) update(1, 1, m + 1, p[i].second, p[i].first);
  int ans = 0;
  int t = 0, hs = 0;
  for (int i = 1; i <= n; i++)
    t = (t * MM + 1) % 1000000007, hs = (hs * MM + a[i]) % 1000000007;
  for (int i = n; i <= m; i++) {
    if (val[1] == hs) ans++;
    if (i < m) update(1, 1, m + 1, p[i + 1].second, p[i + 1].first);
    update(1, 1, m + 1, p[i - n + 1].second, -p[i - n + 1].first);
    hs = (hs + t) % 1000000007;
  }
  println(ans);
  return 0;
}
