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(){
  int N; scanf("%d", &N);
  int K; scanf("%d", &K);
  char S[50] = {};
  int i;
  for(i = 0; i <= N; i++){
    scanf("%c", &S[i]);
    if(i == K){
      if(S[i] == 'A') S[i] = 'a';
      if(S[i] == 'B') S[i] = 'b';
      if(S[i] == 'C') S[i] = 'c';
    }
  }

  printf("%s", S);

  return 0;
}