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(){
  int n;
  int k;
  scanf("%d %d",&n,&k);
  char s[n];
  scanf("%s",s);
  for(int i=0;i<n;i++){
    if(i+1==k){
      s[i]=tolower(s[i]);
    }
    printf("%c",s[i]);
  }
  return 0;
}