We define the interleaving of two natural numbers with d digits
x=x_{d}x_{d−1}… x_{2}x_{1} and y=y_{d}y_{d−1}… y_{2}y_{1}
as x_{d}y_{d}x_{d−1}y_{d−1}… x_{2}y_{2}x_{1}y_{1}.
For example, the interleaving of 4123 and 5679 is 45162739.
Write a program that reads pairs of natural numbers
and prints their interleavings.

For the sake of practice, define and use a function

int interleaving(int x, int y);

to compute the interleaving of two natural numbers x and y.

Input

Input consists of several pairs of natural numbers with the same number of digits.

Output

Print the interleaving of every given pair.

Observation

To avoid overflows, no given number will have more than four digits, but your program should not take this fact into account.

Public test cases

**Input**

4123 5679 312 435 22 91 8 7 3 0 0 3 0 0

**Output**

45162739 341325 2921 87 30 3 0

Information

- Author
- Professors de P1
- Language
- English
- Translator
- Salvador Roura
- Original language
- Catalan
- Other languages
- Catalan
- Official solutions
- C++ Python
- User solutions
- C++ Python