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 Kotlin (1.0.0) (judge verdict: Accepted)

import java.lang.Math

val MOD: Int = 1000000000 + 7
val MODL: Long = MOD.toLong()

fun main(args: Array<String>)
{
    val n = read().toInt()
    val s = read().toCharArray()

    var ans = 0
    for (i in 0 until n-2) {
        ans += if (s[i] == 'A' && s[i+1] == 'B' && s[i+2] == 'C') 1 else 0
    }

    println(ans)
}

fun read(): String = readLine()!!