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>
using namespace std;
using ll = long long;
#define fi first
#define se second
#define pb push_back
#define all(v) (v).begin(),(v).end()
ll mod = 1000000007;
ll INF = 1000000099;



signed main(){
    int n,k;
    string s;
    cin>>n>>k>>s;

    if(s.at(k-1)=='A'){
        s.at(k-1)='a';
    }
    if(s.at(k-1)=='B'){
        s.at(k-1)='b';
    }if(s.at(k-1)=='C'){
        s.at(k-1)='c';
    }

    cout << s << endl;
}