Problem:
Score : 200 points

Problem Statement

We have a string S of length N consisting of uppercase English letters.

How many times does ABC occur in S as contiguous subsequences (see Sample Inputs and Outputs)?

Constraints

3 \leq N \leq 50

S consists of uppercase English letters.

Input

Input is given from Standard Input in the following format:

N
S

Output

Print number of occurrences of ABC in S as contiguous subsequences.

Sample Input 1

10
ZABCDBABCQ

Sample Output 1

2

Two contiguous subsequences of S are equal to ABC: the 2-nd through 4-th characters, and the 7-th through 9-th characters.

Sample Input 2

19
THREEONEFOURONEFIVE

Sample Output 2

0

No contiguous subsequences of S are equal to ABC.

Sample Input 3

33
ABCCABCBABCCABACBCBBABCBCBCBCABCB

Sample Output 3

5

Solution in Ruby (2.3.3) (judge verdict: Accepted)

n=gets.to_i
s=gets.chomp
#cnt=0
#ans=0
#s.each do|c|
  #if cnt==0 and c=="A"
    #cnt+=1
  #elsif cnt==1 and c=="B"
    #cnt+=1
  #elsif cnt==2 and c=="C"
    #ans+=1
    #cnt=0
  #else
    #cnt=0
  #end
#end
#puts ans
puts s.scan(/(ABC)/).size