#include <bits/stdc++.h> using namespace std; int a[25005], b[25005];

int main() { int x, y, n, s = 0; cin >> n >> x >> y; for (int i = 0; i < n; i++) { cin >> a[i] >> b[i];

}
sort(a, a + n);
sort(b, b + n);
for (int i = 0; i < n; i++) {
	if (a[i] > b[i])
		s = s + (a[i] - b[i]) * y;
	if (a[i] < b[i])
		s = s + (b[i] - a[i]) * x;

}
cout << s ;
return 0;

}