At the entrance examination for the magistracy of the MSU Cyber-Mechanics Department Sasha got the question about Ford-Fulkerson algorithm. He knew the topic perfectly as he worked with it many times on programming competition. As the task for the question he was given a network with partially build flow that he had to use in order to demonstrate the workflow of the algorithm. He quickly finished to write the text and took a look at the problem only to understand that the given network is incorrect! Suppose you are given a directed graph G ( V , E ) with two special nodes s and t called source and sink. We denote as n the number of nodes in the graph, i.e. n = | V | and m stands for the number of directed edges in the graph, i.e. m = | E | . For the purpose of this problem we always consider node 1 to be the source and node n to be the sink. In addition, for each edge of the graph e we define the capacity function c ( e ) and flow function f ( e ) . Function f ( e ) represents the correct flow if the following conditions are satisfied: For each edge the flow is non-negative and does not exceed capacity c ( e ) , i.e. 0 ≤ f ( e ) ≤ c ( e ) . For each node , that is not source or sink ( v ≠ s and v ≠ t ) the sum of flows of all edges going in v is equal to the sum of the flows among all edges going out from v . In other words, there is no flow stuck in v . It was clear that as the exam was prepared last night and there are plenty of mistakes in the tasks. Sasha asked one of the professors to fix the network or give the correct task, but the reply was that the magistrate student should be able to fix the network himself. As the professor doesn't want the task to become easier, he asks Sasha to fix the network in a such way that the total number of changes is minimum possible. Sasha is not allowed to remove edges, add new ones or reverse the direction of existing edges. The only thing he is able to do is to change capacity function c ( e ) and flow function f