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 5.4.1) (judge verdict: Runtime Error)

#include <stdio.h>
#include <string.h>
int main(){   
    int N,K,S;
    char ptr[1000];
   
    scanf("%d %d",&N,&K);
    scanf("%s",ptr);

    if(strcmp(ptr[K-1],"A")== 0){
       ptr[K-1] ="a";
    }else if(strcmp(ptr[K-1],"B")==0){
        ptr[K-1]="b";
    }else if(strcmp(ptr[K-1],"C")==0){
        ptr[K-1]="c";
    }
    
    for(S=0;S<N;S++){
        printf("%c",ptr[S]);
    }

    return 0;
}