#icpc2013springg. [icpc2013spring_g]Revenge of Minimum Cost Flow
[icpc2013spring_g]Revenge of Minimum Cost Flow
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Problem Statement
Flora is a freelance carrier pigeon. Since she is an excellent pigeon, there are too much task requests to her. It is impossible to do all tasks, so she decided to outsource some tasks to Industrial Carrier Pigeon Company.
There are cities numbered from 0 to . The task she wants to outsource is carrying freight units from city to city . There are pigeons in the company. The -th pigeon carries freight from city to , and carrying cost of units is if is smaller than or equals to , otherwise . Note that -th pigeon cannot carry from city to . Each pigeon can carry any amount of freights. If the pigeon carried freight multiple times, the cost is calculated from total amount of freight units he/she carried.
Flora wants to minimize the total costs. Please calculate minimum cost for her.
Input
The test case starts with a line containing five integers (), (), (), () and (). You may assume . Each of the next lines contains five integers (), (), (), () and (). Each denotes -th pigeon's information. You may assume at most one pair of and satisfies , all others satisfies .
Output
Print the minimum cost to carry freight units from city to city in a line. If it is impossible to carry, print "Impossible" (quotes for clarity).
Sample Input 1
2 2 0 1 5
0 1 3 0 3
0 1 2 1 6
Output for the Sample Input 1
9
Sample Input 2
4 4 0 3 5
0 1 3 0 3
1 3 3 0 3
0 2 2 1 6
2 3 2 1 6
Output for the Sample Input 2
18
Sample Input 3
2 1 0 1 1
1 0 1 0 1
Output for the Sample Input 3
Impossible
Sample Input 4
2 2 0 1 2
0 1 5 1 2
0 1 6 3 1
Output for the Sample Input 4
9
Sample Input 5
3 3 0 2 4
0 2 3 4 2
0 1 4 1 3
1 2 3 1 1
Output for the Sample Input 5
14
Source Name
Japan Alumni Group Spring Contest 2013