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: Accepted)

#include<stdio.h>
int main()
{
    int n, k;
    char s[51] = "";
    scanf("%d %d", &n, &k);
    scanf("%s", s);

    for (size_t i = 0; i < n; i++)
    {
        if (i+1 == k)
        {
            printf("%c", s[i] + 32);
        } else {
            printf("%c", s[i]);
        }
    }
    printf("\n");
    return 0;
}