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 (Clang 3.8.0) (judge verdict: Accepted)

#include <stdio.h>
#include <ctype.h>

int main()
{
    char str[55];
    char ch;
    int n, k;

    scanf("%d %d", &n, &k);
    k--;

    for (int i = 0; i < n; i++) {
        scanf(" %c", &ch);

        if (i == k) {
            ch = tolower(ch);
        }

        putchar(ch);
    }
    putchar('\n');
    
    return 0;
}