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 Pascal (FPC 3.0.4) (judge verdict: Accepted)

program main;
var 
    a : string;
    i,n,c : integer;
begin
    c := 0;
    readln(n);
    readln(a);
    for i := 1 to n do
        if a[i] = 'A' then 
            if a[i+1] = 'B' then 
                if a[i+2] = 'C' then 
                    inc(c);
    writeln(c);
end.