题目描述

题目描述 The game “The Pilots Brothers: following the stripy elephant” has a quest where a player needs to open a refrigerator. There are 16 handles on the refrigerator door. Every handle can be in one of two states: open or closed. The refrigerator is open only when all handles are open. The handles are represented as a matrix 4х4. You can change the state of a handle in any location [i, j] (1≤i,j≤4). However, this also changes states of all handles in row i and all handles in column j. The task is to determine the minimum number of handle switching necessary to open the refrigerator.

输入描述: The input contains four lines. Each of the four lines contains four characters describing the initial state of appropriate handles. A symbol “+” means that the handle is in closed state, whereas the symbol “−” means “open”. At least one of the handles is initially closed.

输出描述: The first line of the input contains N – the minimum number of switching. The rest N lines describe switching sequence. Each of the lines contains a row number and a column number of the matrix separated by one or more spaces. If there are several solutions, you may give any one of them. 

输入 

-+-- ---- ---- -+--

输出 

6 1 1 1 3 1 4 4 1 4 3 4 4