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

const int N = 1e6 + 6;

int n;
int a[N], b[N];
int ans[N];
int x, y;

stack<int> t;
int sum = 0;

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int res = -1e18;
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> a[i] >> b[i];
    cin >> x >> y;
    for (int i = 1; i <= n; i++) {
        ans[i] += sum * y;
        while (t.size() > 0 && a[t.top()] <= a[i])
            sum -= b[t.top()], t.pop();
        t.push(i);
        sum += b[i];
    }
    t = {};
    sum = 0;
    for (int i = n; i > 0; i--) {
        ans[i] += sum * y;
        while (t.size() > 0 && a[t.top()] <= a[i])
            sum -= b[t.top()], t.pop();
        t.push(i);
        sum += b[i];
    }
    for (int i = 1; i <= n; i++)
        res = max(res, ans[i] + b[i] * y - a[i] * x);
    cout << res;
    return 0;
}