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: Runtime Error)

#include <stdio.h>

int main()
{
	int n,k;	char s[n];	scanf("%d %d %s",&n,&k,s);
	if(s[k-1]=='A')	s[k-1]='a';
	else if(s[k-1]=='B')	s[k-1]='b';
	else if(s[k-1]=='C')	s[k-1]='c';
	printf("%s",s);
	return 0;
}