Count no of different places tommy can cover from home to school condition is one place can't be visited twice and after reaching school he can't proceed further.

Tommy reach school frm his home there are many places b/w their home and school connected by bidirectional paths u have to count no of different places he can cover from home to school condition is one place can't be visited twice and after reaching school he can't proceed further.
you have
given:-
Input
t
n m h s
m lines
Output:
count
t is  number of test case
n is number of nodes,m id number of bidirectional path, h is home and s is school
m lines bidirectional path b/w nodes x and y.
out put count is number of different nodes he can go from school satisfying the condition.
Sample Input:
1
3 3 0 1
0 1
1 2
0 2
Sample Output:
3