import java.util.Arrays;
import java.util.Scanner;
public class lol1 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int N = input.nextInt();
int A, B, C;
A = input.nextInt();
B = input.nextInt();
C = input.nextInt();
int bestMilk = N * A;
int[] X = new int[N];
int[] Y = new int[N];
for (int i = 0; i < N; i++) {
X[i] = input.nextInt();
Y[i] = input.nextInt();
}
for (int temp = 1; temp <= 1000_000_000; temp++) {
int totalMilk = 0;
for (int i = 0; i < N; i++) {
if (temp >= X[i] && temp <= Y[i]) {
totalMilk += B;
} else if (temp < X[i]) {
totalMilk += A;
} else {
totalMilk += C;
}
}
if (totalMilk > bestMilk) {
bestMilk = totalMilk;
}
}
System.out.println(bestMilk);
}
}