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: Runtime Error)

#include <iostream>

using namespace std;

int main()
{
    int n,k;
    char *s;
    cin >> n >> k;
    while(n>=1 && k>=1 && k<=n){
	for(int i = 0;i <n;i++){
		cin >> s[i];
	}
	s[k-1] = s[k-1]+32;
	cout << s << endl;
	cin >> n >> k;
    }
    return 0;
}