Problem:
Score : 100 points

Problem Statement

You are given a string S of length N consisting of A, B and C, and an integer K which is between 1 and N (inclusive).
Print the string S after lowercasing the K-th character in it.

Constraints

1 ≤ N ≤ 50

1 ≤ K ≤ N

S is a string of length N consisting of A, B and C.

Input

Input is given from Standard Input in the following format:

N K
S

Output

Print the string S after lowercasing the K-th character in it.

Sample Input 1

3 1
ABC

Sample Output 1

aBC

Sample Input 2

4 3
CABA

Sample Output 2

CAbA

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

#include<stdio.h>
#include<ctype.h>
int main()
{

    int n,k,i;
    scanf("%d %d",&n,&k);
    char s[n];
    scanf("%s",&s);
    if(k>=1&&k<=n&&n>=1)
    {
        for(i=0;i<=n;i++)
        {
            if(i==k-1)
            {
                printf("%c",tolower(s[i]));
            }
            else
            {
               printf("%c",toupper(s[i]));
            }
        }
    }
    return 0;
}