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++ (GCC 9.2.1) (judge verdict: Accepted)

#include<bits/stdc++.h>
using namespace std; 
typedef long long ll;
typedef long double ld;
#define fr first
#define sc second
#define pb push_back
const ll mod = 1e9+7;
const int N = 2e5+205;
void solve(){
	int n,k; 
	cin>>n>>k;
	string s; 
	cin>>s; 
	s[k-1] = tolower(s[k-1]);
	cout<<s<<endl;
}
int main(){
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	int t=1; 
//	cin>>t; 
	while(t--){
		solve();
	}
	return 0;
}