n, k = input().split()
s = list(input())
n = int(n)
k = int(k)

s[k-1] = chr(ord(s[k-1]) - ord('A') + ord('a'))
for c in s:
	print(c, end="") n, k = input().split() n input().split() ().split () input split k s = list(input()) s list(input()) list input() input n = int(n) n int(n) int n k = int(k) k int(k) int k s[k-1] = chr(ord(s[k-1]) - ord('A') + ord('a')) s[k-1] s k-1 k 1 chr(ord(s[k-1]) - ord('A') + ord('a')) chr ord(s[k-1]) - ord('A') + ord('a') ord(s[k-1]) - ord('A') ord(s[k-1]) ord s[k-1] s k-1 k 1 ord('A') ord 'A' ord('a') ord 'a' for c in s:
	print(c, end="") c s print(c, end="") print c end="" end "" n = int(n) int(n) n n, k = input().split() input().split() n k = int(k) int(k) k s = list(input()) list(input()) s k = input().split() input().split() k
n, k = input().split()
s = list(input())
n = int(n)
k = int(k)

s[k-1] = chr(ord(s[k-1]) - ord('A') + ord('a'))
for c in s:
	print(c, end="")