求调0pts，玄两罐

#include <bits/stdc++.h>
using namespace std;
int n, m, k;
long long sm = 0;
struct Node {
    int x, y;
} a[100010], b[100010];
bool cmp(Node x, Node y) {
    return x.x < y.x;
}
bool cpp(Node a, Node b) {
    return (a.x - a.y) > (b.x - b.y);
}
int main() {
    cin >> n >> m >> k;
    int r = n, l = 1;
    for (int i = 1; i <= n; i++) {
        cin >> a[i].x >> a[i].y;
    }
    for (int i = 1; i <= m; i++) {
        cin >> b[i].x >> b[i].y;
    }
    sort(a + 1, a + n + 1, cmp);
    sort(b + 1, b + m + 1, cpp);
    for (int i = 1; i <= m; i++) {
        if (b[i].x == b[i].y) {
            sm += 1ll * b[i].y * k;
        } 
        else if (b[i].x - b[i].y > 0) {
            if (a[l].y <= 0) {
                l++;
            }
            sm += (1ll * b[i].y * k + 1ll * b[i].x * a[l].x - 1ll * b[i].y * a[l].x);
            a[l].y--;
        } 
        else {
            if (a[r].y <= 0) {
                r--;
            }
            sm += (1ll * b[i].y * k + 1ll * b[i].x * a[r].x - 1ll * b[i].y * a[r].x);
            a[r].y--;
        }
    }
    cout << 2ll * sm <<'\n';
    return 0;
}