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

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++
- User solutions
- C++