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<vector>
#include<string>
#include<algorithm>
#include<utility>
#include<map>
#include<queue>
#include<set>
#include<bitset>
#include<stdio.h>
#include<deque>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
typedef long long ll;
 
int main()
{
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    s[k-1] += 0x20;
    cout << s << endl;
    return 0; 
}