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;
 
int main() {
    int i;
    int n,k;
    string s;
    cin>>n>>k;
    cin >>s;
    if(s[k-1]=='A')s[k-1]='a';
    if(s[k-1]=='B')s[k-1]='b';
    if(s[k-1]=='C')s[k-1]='c';
    int ans=0;
    n=3;
    for (i=0;i<n;i++){
        if(s[i]=='1')ans++;
        
    }
    cout<<s<<endl;
}