Problem Statement

We have a $3×3$ square grid, where each square contains a lowercase English letters. The letter in the square at the $i$-th row from the top and $j$-th column from the left is $c_{ij}$.

Print the string of length $3$ that can be obtained by concatenating the letters in the squares on the diagonal connecting the top-left and bottom-right corner of the grid, from the top-left to bottom-right.

Constraints

• Input consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

c_{11}c_{12}c_{13}
c_{21}c_{22}c_{23}
c_{31}c_{32}c_{33}

Output

Print the string of length $3$ that can be obtained by concatenating the letters on the diagonal connecting the top-left and bottom-right corner of the grid, from the top-left to bottom-right.