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;

    scanf("%d %d",&N,&K);
    char s[N];
    scanf("%s",s);
    if(s[K-1]>=97&&s[K]<=122){
        s[K-1]=s[K-1]-32;
    }else{
        s[K-1]=s[K-1]+32;
    }
    for(int i=0;i<N;i++){
        printf("%c",s[i]);
    }
    return 0;
}