**Cantor Fractions
**

In the late XIXth century the German mathematician George Cantor
argued that the set of positive fractions **Q**^{+}
is equipotent to the set of
positive integers **N**, meaning that they are both infinite,
but of the same class.
To justify this, he exhibited a mapping from
**N** to **Q**^{+} that is onto.
This mapping is just *traversal* of the
**N** x **N** plane that covers all the pairs:

The first fractions in the Cantor mapping are:

Write a program that finds the *i*-th Cantor fraction
following the mapping outlined above.

The inputs consists of several lines with a positive integer number *i* each one.

The output consists of a line per input case, that contains the *i*-th fraction,
with numerator and denominator separed by a slash (/).
The fraction should **not** be in the most simple form.

**Sample Input**

6

**Sample Output**

1/3