Undetected Error

Time Limit: 1.5 sec

**The Problem**

After a test of a code, Mina detect **X** errors and Rina discovered **Y** errors in the same code. There are **Z** errors in common.

If the total error are **A**, estimate the number of errors that are still undetected.

**The Input**

The first line contains a positive integer **T** ( **1<=T<=100000**), denoting the number of test cases. The next T lines will contain 4 integers **X, Y, Z,** and **A**.

**The Output**

For each test case, output one line in the format **"Case m: n"** (quotes for clarity), where **m** is the case number and **n** is the number of errors that are still undetected by Mina and Rina.

**Sample Input**

2

2 3 1 6

5 3 2 10

**Sample Output**

Case 1: 2

Case 2: 4

Online Practice Contest 2 [School & College Level]

Problem Setter: Shahin ShamS