Problem A
Yet Satisfiability Again!

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Input

The first line of input contains a single integer, not more than $5$, indicating the number of test cases to follow. The first line of each test case contains two integers $n$ and $m$ where $1\le n\le 20$ indicates the number of variables and $1\le m\le 100$ indicates the number of clauses. Then, $m$ lines follow corresponding to each clause. Each clause is a disjunction of literals in the form X$i$ or ~X$i$ for some $1\le i\le n$, where ~X$i$ indicates the negation of the literal X$i$. The “or” operator is denoted by a ‘v’ character and is seperated from literals with a single space.

Output

For each test case, display satisfiable on a single line if there is a satisfiable assignment; otherwise display unsatisfiable.

2
3 3
X1 v X2
~X1
~X2 v X3
3 5
X1 v X2 v X3
X1 v ~X2
X2 v ~X3
X3 v ~X1
~X1 v ~X2 v ~X3

satisfiable
unsatisfiable