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 <bits/stdc++.h>
using namespace std;
int main()
{
  string s;
  cin>>s;
  string aa = s.substr(0,2);
  string bb = s.substr(2,2);
  if(stoi(aa)>12&&stoi(bb)<=12&&stoi(bb)>0)
  {
    cout<<"YYMM"<<endl;
  }
  else if(stoi(bb)>12&&stoi(aa)<=12&&stoi(aa)>0)
  {
    cout<<"MMYY"<<endl;
  }
  else if(stoi(aa)<=12&&stoi(aa)>0&&stoi(bb)<=12&&stoi(bb)>0)
  {
    cout<<"AMBIGOUS"<<endl;
  }
  else
  {
    cout<<"NA"<<endl;
  }
}