Author:  G. Grenkin, A. Klenin  Time limit:  1 sec  
Input file:  input.txt  Memory limit:  256 Mb  
Output file:  output.txt 
Two fathers and two sons walked together... It is well known that this could describe a group of either 3 or 4 people.
Now let's say that A fathers and B sons walked together. Could it be that this group consisted of exactly N different persons?
A person is counted as a father if there is his son among the group. A person is counted as a son if there is his father among the group. Each father can have one or more sons, each son must have exactly one father. Father of a person can not be this person's descendant. Each person must me either a son, a father, or both.
Your program must, given numbers A B N, output corresponding fatherson relationship or determine that it does not exist.
Input file contains integers A B N.
Output file must contain a number of fatherson relationships M followed by M pairs a_{i} b_{i} where a_{i} is a number of the father, b_{i} is a number of the son (1 ≤ a_{i}, b_{i} ≤ N).
All pairs must be different. If there are several solutions, output any of them. If it is impossible for a group to consist of N persons, output file must contain a single integer 0.
1 ≤ A ≤ B ≤ 100
1 ≤ N ≤ 200
No.  Input file (input.txt ) 
Output file (output.txt ) 

1 


2 


3 

