The Amestris government has been alerted of imaxblue's plan, and has decided to shut down all bidirectional roads between its
cities, numbered
to
. However, they are going to be slowly reopening roads, at a steady rate of
road per day, for days
to
. imaxblue knows their plan, and will only move between two cities if he knows that they are in the same strangely connected component. He will ask
queries in the form "
", asking the first day on which
and
will be strangely connected, or
if it will never be strangely connected.
Note: We define a strangely connected component as a connected component that will not be disconnected by removing any 1 edge.
Input Specification
First line: 
Next
lines:
integers
and
, representing that cities
and
are connected on the
day.
Next
lines:
integers
and
, representing a query.
Subtasks
For full points,
.
For 5/25 points,
.
Sample Input
Copy
4 5 3
3 3
1 3
3 0
3 2
2 3
0 2
3 3
0 3
Sample Output
Copy
-1
0
-1
Comments