String
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 262144/262144 K (Java/Others)Total Submission(s): 1538 Accepted Submission(s): 691
Problem Description
Avin has a string. He would like to uniform-randomly select four characters (selecting the same character is allowed) from it. You are asked to calculate the probability of the four characters being ¡±avin¡± in order.
Input
The first line contains n (1 ¡Ü n ¡Ü 100), the length of the string. The second line contains the string. To simplify the problem, the characters of the string are from ¡¯a¡¯, ¡¯v¡¯, ¡¯i¡¯, ¡¯n¡¯.
Output
Print the reduced fraction (the greatest common divisor of the numerator and denominator is 1), representing the probability. If the answer is 0, you should output "0/1".
Sample Input
4 avin 4 aaaa
Sample Output
1/256 0/1