Apartments.cpp

//Apartments - https://cses.fi/problemset/task/1084/

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

const int MOD = 1e9 + 7;
const ll INF = 1e18;

void solve() {
    int n, m, k;
    cin >> n >> m >> k;
    vector<int> a(n), b(m);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    for (int i = 0; i < m; i++) {
        cin >> b[i];
    }

    sort(a.begin(), a.end());
    sort(b.begin(), b.end());

    int ans = 0;
    int i = 0, j = 0;
    while (i < n && j < m) {
        if (b[j] > a[i] + k) {
            i++;
        } else if (b[j] < a[i] - k) {
            j++;
        } else {
            i++;
            j++;
            ans++;
        }
    }
    cout << ans << endl;
}


int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int T = 1;
//    cin >> T;
    while (T--) {
        solve();
    }
    return 0;
}