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 Rust (1.15.1) (judge verdict: Accepted)

use std::io;

fn main() {
	let mut buf = String::new();
	io::stdin().read_line(&mut buf).expect("");
	let mut buf = String::new();
	io::stdin().read_line(&mut buf).expect("");
	let mut cnt = 0;
	for number in 0..(buf.len() - 3) {
		let s = &buf[number..(number+3)];
		if s == "ABC" {
			cnt = cnt + 1;
		}
	}
	println!("{}", cnt);
}