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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php



fscanf(STDIN,"%d",$N);
fscanf(STDIN,"%s",$S);

$count = 0;

for($i=0;$i<$N;$i++){
    if($S[$i] == 'A' && $S[$i+1] == 'B' && $S[$i+2] == 'C'){ 
        $count++;
    }
}

echo $count."\n";