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<string.h>
#include<math.h>

int main(void) {

	double p;
	int count;
	int i;
	int n, k;
	double posi=0;
	int h;
	
	h=scanf("%d %d", &n, &k);
	for (i = 1; i <= n; i++) {
		p = i;
		count = 0;
		while (p<k) {
			p = p * 2;
			count++;
		}
		posi = posi + pow(0.5000, count)/n;
	}
	printf("%lf", posi);
	return 0;
}