说明

Vera has five sticks of distinct lengths l1, l2, l3, l4, l5. Vera may choose any three of the five sticks to form the sides of a triangle. How many different triangles can Vera make? Each triangle must have positive area and sticks cannot be bent or cut.

输入格式

Line 1 contains integers l1, l2, l3, l4, l5 (1 ≤ li ≤ 1000). 

输出格式

Print one line with one integer, the number of ways to form a triangle. 

1 2 3 4 5

3

Source

Waterloo170930 洛谷