Collections Module II

Let's solve another interesting problem using collections module.

There are N customers who bought items, the list is represent as item id and price.

Your task is to print each item id and total price(quantity * price) in order of its first occurrence.

1 <= N <= 10⁵

1 <= item id, price <= 10⁹

First line consist of integer N.

Each of the next N lines consist of two space separated integers item id and price of item.

Print each item id and total price(quantity * price) in order of its first occurrence.

Note: There should be exactly one space after each integers you printed.

Input 1:

9
10 10
2 5
10 10
2 5
1 2
1 2
10 10
4 5
2 5

Input 2:

4
1 2
1 2
2 2
1 2

Output 1:

10 30 
2 15 
1 4 
4 5 

Output 2:

1 6 
2 2 

Explanation 1:

Item with id 10 comes first, followed by 2, 1, 4.
So, print the item in order of its first occurence.

Explanation 2:

Item with id 1 comes first, followed by 2.