Teachers and parrents

Instructions:

The table describes the number of passengers entering and leaving at stations A, B, C ... Bus arrives without passengers at the first station. All passengers get off on the last station. We do keep rules of decency - first get off and then get in.

Example

 
A
B
C
D
E
 got off 
0 0
 got on 
3 3
5 0
4 8
0 0
 in bus
5 8
4 6
9 0
11 8
 altogether
13


Solution

 
A
B
C
D
E
 got off 
0 0
4 5
0 6
2 0
11 8
 got on 
5 8
3 3
5 0
4 8
0 0
 in bus
5 8
4 6
9 0
11 8
 altogether
13
10
9
19


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