Goal
Bob has a bathtub.
He wants to fill it with water but there are some leaks that let the water flow.
Given the dimensions S and h of the bathtub, the tap water flow and the leakHeight and leakFlow of each leak, calculate the time, rounded to the second down, Bob needs to fill his bathtub.
A leak does not leak the water flow until the water has reached the leak height.
The bathtub is a rectangular parallelepiped of surface area S and height h.
Input
Line 1 : An integer S for the surface area of the bathtub in cm².
Line 2 : An integer h for the height of the bathtub in cm.
Line 3 : An integer flow for the tap water flow in L/minute.
Line 4 : An integer N for the number of leaks.
N next lines : 2 space-separated integers leakHeight and leakFlow for the height of the leak in cm and the flow allowed by the leak (in L/minute).
Output
If the bathtub can be filled, output one line :
The time, in HH:MM:SS format, rounded to the second down, that Bob needs to fill his bathtub.
if the bathtub cannot be filled entirely, output one line :
Impossible, filling height cm.
Constraints
0≤N≤1000
0≤leakHeight<h
0<time≤99:59:59
0<Sxh<2^32
Example
Input
12750
60
12
2
20 1
45 3
