Ladies and gentlemen, please sit up straight.
Don't tilt your head. I'm serious.
For n given strings S1,S2,⋯,Sn, labelled from 1 to n, you should find the largest i (1≤i≤n) such that there exists an integer j (1≤j<i) and Sj is not a substring of Si.
A substring of a string Si is another string that occurs in Si. For example,
ruiz" is a substring ofruizhang", and
rzhang" is not a substring ofruizhang".
The first line contains an integer t (1≤t≤50) which is the number of test cases.
For each test case, the first line is the positive integer n (1≤n≤500) and in the following n lines list are the strings S1,S2,⋯,Sn.
All strings are given in lower-case letters and strings are no longer than 2000 letters.
For each test case, output the largest label you get. If it does not exist, output −1.
Case #1: 4
Case #2: -1
Case #3: 4
Case #4: 3