Get equal#645
There are cards on the table, each with a number written on it. Additionally, there is a large stack of blank cards available. In one move, you may remove from the table two cards with equal numbers, then take two blank cards from the stack, write a number on each of them, and put them on the table.
Determine how to make all the numbers on the cards on the table equal in the minimum number of moves.
The first line contains the number of cards (1 \leq N \leq 30000). The second line contains numbers, representing the numbers written on the cards. All numbers are positive integers not exceeding 10^9.
Print the minimum number of operations needed so that all cards on the table have the same number. On each of the next lines, print four numbers describing the respective move: the first and second numbers are those written on the cards being removed, the third and fourth are the numbers to write on the new cards. If it is impossible to make all cards have the same number, print the single number .
Example 1