Competitions

# Simple Combinatorics

# Diagonal

The number of diagonals of an **n**-gon is not less than **N**. What is the minimum possible value of **n**?

#### Input

Contains less than **1001** lines. Each line contains a positive integer **N** (**N** ≤ `10`

) that indicates the minimum possible number of diagonals. Input is terminated by a line with one ^{15}**0** that should not be processed.

#### Output

For each test case produce one line that contains serial number and the minimum possible value for **n** (number of sides).

Input example #1

10 100 1000 0

Output example #1

Case 1: 7 Case 2: 16 Case 3: 47