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 (Clang 3.8.0) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <math.h>
int main(void){
  int s;
  int a,b,f1,f2;
  a=floor(s/100)*100;
  b=s%100;
  if((a<13)&&(a)&&(b>13))f1=1;
  if((b<13)&&(b)&&(a>13))f2=1;
  if((a<13)&&(a)&&(b)&&(b<13)){
    printf("AMBIGUOUS\n");
    f1=0;
    f2=0;
  }
  if((!a)||(!b))printf("NA\n");
  if(f1)printf("MMYY");
  if(f2)printf("YYMM");
  return 0;
}