Try this:

Input:
19 5
learn 1 1
learn 1 2
learn 1 3
learn 1 4
rollback 1
rollback 1
relearn 1
clone 1
check 2
relearn 2
check 2
rollback 2
rollback 2
check 2
rollback 2
check 2
check 1
relearn 1
check 1

Expected output:
3
4
2
1
3
4