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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"fmt"
	//"math"
	"strings"
)

func main() {
	var n,k int
	var s string
	fmt.Scan(&n,&k,&s)
 
	str := strings.Split(s,"")
	str[k-1] = strings.ToLower(str[k-1])
 
	fmt.Println(strings.Join(str,""))
}