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)

int main(){
 
  int n, k;
  char s[50];
 
  scanf("%d %d",&n,&k);
 
  scanf("%s",s);
 
  if(n >= k){
    if(s[k-1] < 'a'){
      s[k-1] = s[k-1]+32;
    }else{
      s[k-1] = s[k-1]-32;
    }
  }
  printf("%s\n",s);
 
  return 0;
 
 
}