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 Scala (2.11.7) (judge verdict: Runtime Error)

object Main extends App {
  val n = scala.io.StdIn.readLine.toInt
  val s = scala.io.StdIn.readLine
  var cnt = 0
  (0 to s.length - 2).foreach { i =>
    if (s(i) == 'A' && s(i + 1) == 'B' && s(i + 2) == 'C')
      cnt += 1
  }
  println(cnt)
}