---

#include <iostream>
#include <vector>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n, k;
    if (!(cin >> n >> k)) return 0;

    vector<long long> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }

    vector<long long> t(k);
    for (int i = 0; i < k; i++) {
        cin >> t[i];
    }
    if (k == 1) {
        cout << n << "\n";
        return 0;
    }
    vector<long long> da(n - 1);
    for (int i = 0; i < n - 1; i++) {
        da[i] = a[i + 1] - a[i];
    }
    vector<long long> dt(k - 1);
    for (int i = 0; i < k - 1; i++) {
        dt[i] = t[i + 1] - t[i];
    }
    int m = dt.size();
    int sz = da.size();

    vector<int> lps(m, 0);
    int dlug = 0;
    int cos = 1;

    while (cos < m) {
        if (dt[cos] == dt[dlug]) {
            dlug++;
            lps[cos] = dlug;
            cos++;
        } else {
            if (dlug != 0) {
                dlug = lps[dlug - 1];
            } else {
                lps[cos] = 0;
                cos++;
            }
        }
    }

    int pas = 0;
    int j = 0;
    int i = 0;

    while (i < sz) {
        if (da[i] == dt[j]) {
            i++;
            j++;
        }
        if (j == m) {
            pas++;
            j = lps[j - 1];
        } else if (i < sz && da[i] != dt[j]) {
            if (j != 0) {
                j = lps[j - 1];
            } else {
                i++;
            }
        }
    }

    cout << pas << "\n";

    return 0;
}