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>
#include <string.h>

int main(void){
    int i, n, k;
    scanf("%d %d", &n, &k);
    char s[n];
    scanf("%s", s);
    for(i=0; i<=strlen(s); i++){
        if(s[i]>=65 && s[i]<=90){
            if(i==k-1){
                s[i] += 32;
            }
        }
    }
    printf("%s\n", s);
    return 0;
}