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> 
#include <vector>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define size_of_array(array) (sizeof(array)/sizeof(array[0]))
using ll =long long;
using namespace std;
using Graph=vector<vector<int>>;
using Field=vector<vector<int>>;

template<class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;}return 0;}

int main(){
    int n,k;
    cin>>n>>k;
    string s;
    cin>>s;
    s[k-1]=s[k-1]+' ';
    cout<<s<<endl;
}