A. Candies and Two Sisterstime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputThere are two sisters Alice and Betty. You have n candies. You want to distribute these n candies between two sisters in such a way that:  Alice will get a (a > 0) candies;  Betty will get b (b > 0) candies;  each sister will get some integer number of candies;  Alice will get a greater amount of candies than Betty (i.e. a > b);  all the candies will be given to one of two sisters (i.e. a+b=n). Your task is to calculate the number of ways to distribute exactly n candies between sisters in a way described above. Candies are indistinguishable.Formally, find the number of ways to represent n as the sum of n=a+b, where a and b are positive integers and a>b.You have to answer t independent test cases.InputThe first line of the input contains one integer t (1 \le t \le 10^4) — the number of test cases. Then t test cases follow.The only line of a test case contains one integer n (1 \le n \le 2 \cdot 10^9) — the number of candies you have.OutputFor each test case, print the answer — the number of ways to distribute exactly n candies between two sisters in a way described in the problem statement. If there is no way to satisfy all the conditions, print 0.ExampleInput
6
7
1
2
3
2000000000
763243547
Output
3
0
0
1
999999999
381621773
NoteFor the test case of the example, the 3 possible ways to distribute candies are:  a=6, b=1;  a=5, b=2;  a=4, b=3. 
6
7
1
2
3
2000000000
763243547

3 0 0 1 999999999 381621773 
['math', '*800']