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 Fortran (gfortran v4.8.4) (judge verdict: Accepted)

      PROGRAM piyo
      IMPLICIT NONE
      integer :: n
      character(50) :: s
      integer :: i, ans=0
      
      read*,n
      read*,s
      
      do i = 1,n-2
        if( s(i:i+2)=='ABC' )then
          ans = ans + 1
        end if
      end do
      
      print*,ans
      
      
      
      
      
      END PROGRAM