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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
int main()
{
    int n,i,j,k,number=0;
    char s[100000],s1[4]={'A','B','C'};
    scanf("%d",&n);
    for(i=0;i<n;i++)
        scanf("%c",&s[i]);
    for(i=0;s[i]!=0;i++)
    {
        for(j=i,k=0;s[j]==s1[k];j++,k++)
        {
            if(s1[k+1]=='\0')
                number++;
        }
    }
    printf("%d",number);
    return 0;
}