#include <iostream>
#include <algorithm>
#include <cstring>
typedef long long ll;
const int N = 3e5;
const int INF = 0x3f3f3f3f;
inline int read() {int x; return scanf("%d", &x), x;}
int n[2], m;
int dp[N + 5][2][2];
struct node
{
	int l, r;
	bool operator < (const node &t) const {return l < t.l;}
	bool operator < (const int &t) const {return r < t;}
} block[2][N + 5];
inline int find(int type, int pos)
{
	int t = std :: lower_bound(block[type] + 1, block[type] + n[type] + 1, pos) - block[type];
	return block[type][t].l <= pos ? t : 0;
}
inline int next(int type, int pos)
{
	int t = std :: lower_bound(block[type] + 1, block[type] + n[type] + 1, pos) - block[type];
	return t + (block[type][t].l <= pos);
}
inline void modify(int &x, int y) {x = std :: min(x, y);}
int main()
{
	n[0] = read() + 1, n[1] = read() + 1, m = read();
	for (int i = 1; i < n[0]; i ++ ) block[0][i] = /* */ {read(), read() - 1}; block[0][n[0]] = /* */ {INF, INF}; std :: sort(block[0] + 1, block[0] + n[0] + 1);
	for (int i = 1; i < n[1]; i ++ ) block[1][i] = /* */ {read(), read() - 1}; block[1][n[1]] = /* */ {INF, INF}; std :: sort(block[1] + 1, block[1] + n[1] + 1);
	std :: memset(dp, 0x3f, sizeof dp);
	dp[!block[0][1].l][0][0] = 0;
	int res = 0;
	for (int i = 0; i <= n[0] + n[1]; i ++ )
		for (int cas = 0; cas <= 1; cas ++ )
			for (int j = 0; j <= 1; j ++ )
				for (int k = 0; k <= 1; k ++ )
				{
					int tim = dp[i][j][k];
					if (dp[i][j][k] >= INF) continue;
					int pos = find(j, tim), across = find(j ^ 1, tim + m), after = next(j, tim);
					modify(dp[i + (across && !k)][j ^ 1][find(j, tim + 2 * m) == pos], tim + m);
					modify(dp[i + 1][j][find(j, block[j][after].l + m) == across], block[j][after].l);
				}
	for (int i = n[0] + n[1]; i >= 0; i -- ) if (std :: min({dp[i][0][0], dp[i][0][1], dp[i][1][0], dp[i][1][1]}) < INF) return printf("%d", i), 0;
	return 0;
}