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: Accepted)

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <stdio.h>
int compare(const void *a,const void *b){
    if(*(long long*)a>*(long long*)b)return 1;
    return -1;
}
int main()
{   int a,i,b,x,y,n,m,k;
    scanf("%d%d",&n,&k);
    char s[n+1];
    scanf("%s",s);
    for(i=0;i<n;i++){
    if(i==k-1){
        printf("%c",'a'+s[i]-'A');

    }else 
    printf("%c",s[i]);
    
    }
    
    return 0;
}