n,k = map(int,input().split())
s = list(input())
s[k-1] = s[k-1].lower()
for i in s :
  print(i,end='')
print() n,k = map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split k s = list(input()) s list(input()) list input() input s[k-1] = s[k-1].lower() s[k-1] s k-1 k 1 s[k-1].lower() [k-1].lower [k-1] s k-1 k 1 lower for i in s :
  print(i,end='') i s print(i,end='') print i end='' end '' print() print k = map(int,input().split()) map(int,input().split()) k s = list(input()) list(input()) s n,k = map(int,input().split()) map(int,input().split()) n
n,k = map(int,input().split())
s = list(input())
s[k-1] = s[k-1].lower()
for i in s :
  print(i,end='')
print()