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#include <bits/stdc++.h>
using namespace std;
#define ll long long
int tt, tc;

void solve() {
    int n;
    cin >> n;
    ll v;
    cin >> v;
    // d/v <= a[i], d >= v * a[i]
    vector<ll> a(n), d(n);
    for (ll& u : a) cin >> u;
    for (ll& u : d) cin >> u;

    int ans = 0;
    for (int i = 0; i < n; i++) {
        if (d[i] <= v * a[i]) ans += 1;
    }

    cout << ans << "\n";
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    tt = 1, tc = 1; // cin >> tt;
    while (tt--) solve(), tc++;
}