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 <bits/stdc++.h>

#define INF INT_MAX

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;

int main(void){
 	cin.tie(0);
    ios::sync_with_stdio(false);
    int n,k;
    string s;
    cin >> n >> k >> s;
    s[k-1] = (s[k-1] - 'A') + 'a';
    cout << s << endl;

	return 0;
}