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 <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cstring>
#include <map>
#include <queue>
#include <set>
#include <cassert>
#include <stack>
#include <bitset>
//#include <unordered_set>
#define mkp make_pair
#define err cout<<"here"<<endl
using namespace std;
const double EPS=1e-12;
typedef long long lon;
typedef unsigned long long ull;
typedef set<int>::iterator IT;
const lon SZ=100010,SSZ=30,APB=52,mod=97,one=1;
const lon INF=0x7FFFFFFF;
lon n,m;
struct nd{
	lon to,wt;
	nd(lon a=0,lon b=0):to(a),wt(b){}
};

void init()
{
	cin>>n>>m;
	string str;
	cin>>str;
	--m;
	if(str[m]>='A'&&str[m]<='Z')
	{
		str[m]+=32;
	}
	cout<<str<<endl;
}


void work()
{
	
}

void release()
{
	
}

int main()
{
	std::ios::sync_with_stdio(0);
	//freopen("d:\\1.txt","r",stdin);
	int casenum;
	//cin>>casenum;
	//cout<<casenum<<endl;
	//for(int time=1;time<=casenum;++time)
	//for(int time=1;cin>>n>>m;++time)
	{
		//cout<<"Case #"<<time<<": ";
		init();
		work();
		release();
	}
	return 0;
}