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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <string>
#include <map>
#include <tuple>

using namespace std;

typedef long long ll;

int main(void){
    string s,c;
    ll n,k;
    cin >> n >> k;
    cin >> s;

    c = "abc";
    if(s[k - 1] == 'A'){
        s[k - 1] = c[0];
    }else if(s[k - 1] == 'B'){
        s[k -1] = c[1];
    }else if(s[k - 1] == 'C'){
        s[k - 1] = c[2];
    }
    cout << s << endl;
    return 0;
}