#include <bits/stdc++.h>

using namespace std;

void ckmin(int &x, int y) {
    if (x > y) {
        x = y;
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n[2], k;
    cin >> n[0] >> n[1] >> k;

    vector<pair<int, int>> s[2];
    s[0] = s[1] = {{-1, -1}};

    for (int t = 0; t < 2; ++t) {
        for (int i = 0; i < n[t]; ++i) {
            int l, r;
            cin >> l >> r;
            s[t].push_back({l, r - 1});
        }
    }

    auto find = [&](int t, int x) {
        return lower_bound(s[t].begin(), s[t].end(), pair{x + 1, 0});
    };

    auto in = [&](int t, int x) {
        return prev(find(t, x))->second >= x;
    };

    vector dp(2, vector<int>(n[0] + n[1] + 1, 2e9));
    dp[0][in(0, 0)] = 0;
    int ans = 0;

    for (int i = 0; i < n[0] + n[1]; ++i) {
        for (int m = 0; m < 2; ++m) {
            for (int t = 0; t < 2; ++t) {
                if (dp[t][i] > 1e9) {
                    continue;
                }
                int x = dp[t][i];
                auto p = find(t, x);
                if (p != s[t].end()) {
                    ckmin(dp[t][i + 1], p->first);
                }
                p = prev(p);
                int r = max<int>(x + k, p->second - k + 1);
                int add = find(t ^ 1, r) - find(t ^ 1, x + k) + in(t ^ 1, x + k);
                ckmin(dp[t ^ 1][i + add], r);
            }
        }
    }
    
    for (int x = 0; x <= n[0] + n[1]; ++x) {
        if (dp[0][x] < 2e9 || dp[1][x] < 2e9) {
            ans = x;
        }
    }

    cout << ans << '\n';

    return 0;
}