How to count total item from two file

Question

hey..i got two text file and i need to total up the occurrance in tht two files..
For example:
my first file:
1 2 3 4
1 3 4

my second file:
1 3 4
2 5

After total up the item in this two file:
1: 3
2: 2
3: 3
4:3
 using Dictionary <>  to do this..hope someone will help me...thank you