Vertical Reading

Yeongseok cannot read yet, and he plays with a toy that sticks magnetic letters on a blackboard. The letters in the toy are the uppercase letters A to Z, the lowercase letters a to z, and the digits 0 to 9.

Yeongseok sticks letters in one horizontal row to make a word, then sticks letters in the row below it to make another word. He makes five words this way. One word is 1 to 15 letters stuck next to each other with no gap, and the five words may have different lengths.

When he gets bored, he reads the five words vertically. He first reads the first letter of every word from top to bottom, then the second letter of every word from top to bottom. He keeps moving one position to the right and reads the letters at that position from top to bottom. While he reads position $i$, a word shorter than $i$ letters has no letter there, so he skips that word and continues with the letter of the word right below it.

Given the five words on the blackboard, write a program that prints the letters in the order Yeongseok reads them.

Five lines are given. Each line holds 1 to 15 letters stuck next to each other with no gap. Each letter is an uppercase letter A to Z, a lowercase letter a to z, or a digit 0 to 9. A line has no space at its start or its end.

Print the letters in the order Yeongseok reads them, joined with no spaces, on one line.