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: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>

#define isMonth(x) ( 1 <= x && x <= 12 )

int main(int argc, char const *argv[])
{
	int num, t, b;

	scanf("%d", &num);
	t = num / 100;
	b = num % 100;

	if( isMonth(t) )
	{
		if( isMonth(b) )
			puts("AMBIGUOUS");
		else
			puts("MMYY");
	}
	else
	{
		if( isMonth(b) )
			puts("YYMM");
		else
			puts("NA");
	}

	return 0;
}