//khodaya khodet komak kon
# include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair <int, int> pii;
typedef pair <pii, int> ppi;
typedef pair <int, pii> pip;
typedef pair <pii, pii> ppp;
typedef pair <ll, ll> pll;
# define A first
# define B second
# define endl '\n'
# define sep ' '
# define all(x) x.begin(), x.end()
# define kill(x) return cout << x << endl, 0
# define SZ(x) int(x.size())
# define lc id << 1
# define rc id << 1 | 1
# define fast_io ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
ll power(ll a, ll b, ll md) {return (!b ? 1 : (b & 1 ? a * power(a * a % md, b / 2, md) % md : power(a * a % md, b / 2, md) % md));}
const int xn = 1e6 + 10;
const int xm = - 20 + 10;
const int sq = 320;
const int inf = 1e9 + 10;
const ll INF = 1e18 + 10;
const ld eps = 1e-15;
const int mod[2] = {1000000007, 998244353};
const int base = 257;
int n, m, a[xn], pw[2][xn], inv[2][xn], fen[xn], ans, lazy[xn << 2];
pii seg[xn << 2], hsh, b[xn], sum;
void mofen(int pos, int val){
for (pos += 5; pos < xn; pos += pos & - pos)
fen[pos] += val;
}
int gefen(int pos){
int res = 0;
for (pos += 5; 0 < pos; pos -= pos & - pos)
res += fen[pos];
return res;
}
void shift(int id, int l, int r){
if (!lazy[id])
return;
if (0 < lazy[id]){
seg[id].A = 1ll * seg[id].A * pw[0][lazy[id]] % mod[0];
seg[id].B = 1ll * seg[id].B * pw[1][lazy[id]] % mod[1];
}
else{
seg[id].A = 1ll * seg[id].A * inv[0][- lazy[id]] % mod[0];
seg[id].B = 1ll * seg[id].B * inv[1][- lazy[id]] % mod[1];
}
if (1 < r - l){
lazy[lc] += lazy[id];
lazy[rc] += lazy[id];
}
lazy[id] = 0;
}
void update(int id, int l, int r, int ql, int qr, int val){
shift(id, l, r);
if (qr <= l || r <= ql || qr <= ql)
return;
if (ql <= l && r <= qr){
lazy[id] += val;
shift(id, l, r);
return;
}
int mid = l + r >> 1;
update(lc, l, mid, ql, qr, val);
update(rc, mid, r, ql, qr, val);
seg[id].A = (seg[lc].A + seg[rc].A) % mod[0];
seg[id].B = (seg[lc].B + seg[rc].B) % mod[1];
}
void modify(int id, int l, int r, int pos, pii val){
shift(id, l, r);
if (r - l == 1){
seg[id] = val;
return;
}
int mid = l + r >> 1;
if (pos < mid)
modify(lc, l, mid, pos, val);
else
modify(rc, mid, r, pos, val);
shift(lc, l, mid), shift(rc, mid, r);
seg[id].A = (seg[lc].A + seg[rc].A) % mod[0];
seg[id].B = (seg[lc].B + seg[rc].B) % mod[1];
}
void add(int x, int y){
int y1 = 1ll * y * pw[0][gefen(x)] % mod[0];
int y2 = 1ll * y * pw[1][gefen(x)] % mod[1];
modify(1, 1, m + 1, x, {y1, y2});
update(1, 1, m + 1, x + 1, m + 1, 1);
mofen(x, 1);
}
void rem(int x, int y){
modify(1, 1, m + 1, x, {0, 0});
update(1, 1, m + 1, x + 1, m + 1, - 1);
mofen(x, - 1);
}
int main(){
fast_io;
for (int i = 0; i < 2; ++ i){
pw[i][0] = inv[i][0] = 1;
pw[i][1] = base;
inv[i][1] = power(base, mod[i] - 2, mod[i]);
for (int j = 2; j < xn; ++ j){
pw[i][j] = 1ll * pw[i][j - 1] * pw[i][1] % mod[i];
inv[i][j] = 1ll * inv[i][j - 1] * inv[i][1] % mod[i];
}
}
cin >> n >> m;
for (int i = 1; i <= n; ++ i){
cin >> a[i];
hsh.A = (hsh.A + 1ll * a[i] * pw[0][i - 1] % mod[0]) % mod[0];
hsh.B = (hsh.B + 1ll * a[i] * pw[1][i - 1] % mod[1]) % mod[1];
sum.A = (sum.A + pw[0][i - 1]) % mod[0];
sum.B = (sum.B + pw[1][i - 1]) % mod[1];
}
for (int i = 1; i <= m; ++ i)
cin >> b[i].A, b[i].B = i;
sort(b + 1, b + m + 1);
for (int i = 1; i <= m; ++ i)
swap(b[i].A, b[i].B), b[i].B = i;
sort(b + 1, b + m + 1);
if (m < n)
kill(0);
for (int i = 1; i <= n; ++ i)
add(b[i].B, b[i].A);
ans += (seg[1] == hsh);
for (int i = n + 1; i <= m; ++ i){
add(b[i].B, b[i].A), rem(b[i - n].B, b[i - n].A);
hsh.A = (hsh.A + sum.A) % mod[0];
hsh.B = (hsh.B + sum.B) % mod[1];
ans += (seg[1] == hsh);
}
cout << ans << endl;
return 0;
}
