Problem Statement

Given are integer sequences of length $N$ each: $A = (A_1, \\dots, A_N)$ and $C = (C_1, \\dots, C_N)$.

You can do the following operation any number of times, possibly zero.

• Choose an integer $i$ such that $1 \\leq i \\leq N$ and add $1$ to the value of $A_i$, for a cost of $C_i$ yen (Japanese currency).

After you are done with the operation, you have to pay $K \\times X$ yen, where $K$ is the number of different values among the elements of $A$.

What is the minimum total amount of money you have to pay?

Constraints

• $1 \\leq N \\leq 2 \\times 10^5$
• $1 \\leq X \\leq 10^6$
• $1 \\leq A_i, C_i \\leq 10^6 \\, (1 \\leq i \\leq N)$
• All values in input are integers.

Input

Input is given from Standard Input in the following format:

$N$ $X$ $A_1$ $C_1$ $\\vdots$ $A_N$ $C_N$

Output

Print a number representing the answer.

Sample Input 1

3 5
3 2
2 4
4 3

Sample Output 1

12

After adding $1$ to $A_1$, there will be two different values among the elements of $A$, for a total cost of $C_1 + 2 \\times X = 12$ yen. It is impossible to make the total cost less than this.

Sample Input 2

1 1
1 1

Sample Output 2

1

Sample Input 3

7 7
3 2
1 7
4 1
1 8
5 2
9 8
2 1

Sample Output 3

29