#PUCMM009. David and his Obsession

David and his Obsession

You are walking by an empty corridor at PUCMM. All around you are arithmetic expressions written on the walls and on the floor. You find it odd and quickly realize all these expressions seem to be failed attempts to solve a problem. As you read by, you hear a voice coming from one of the classrooms that is whispering “I do not see it! I do not see it!” You walk to the classroom and find David rolling on the floor in frustration.


“What’s going on, David? you ask.

“The answer.. I do not see! Do you see?” replies David back.

 

“What answer?” you ask him.

“Professor Olson gave me this problem and … I do not see.”

 

“Ok. What about you stand up and describe the problem to me?” you ask again.

“Well, OK. You are pretty smart yourself. Imagine ten slips of paper bearing the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 are put into a hat. 5 slips are drawn at random and laid out in a row in the order in which they were drawn.” He sighs deeply. “What is the probability that the 5-digit number so formed is divisible by 495?”

 

On your backpack there is a laptop. Help him. Write an algorithm that solves the problem.

 

Input

 

There is no input for this problem.

 

Output

 

Print in a single line the answer as a fraction expressed in its lowest terms.

 

Sample cases

 

There are no sample cases for this problem.

 

Notes

In case you need this, the greatest common divisor of (a, b) is defined recursively as follows:

 

gcd(a,b) = b if a == 0, otherwise gcd = gcd(b mod a, a).