n, k = map(int, input().split())
s = input()
ans = s[:k-1] + chr(ord(s[k-1])+32) + s[k:]
print(ans) n, k = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split k s = input() s input() input ans = s[:k-1] + chr(ord(s[k-1])+32) + s[k:] ans s[:k-1] + chr(ord(s[k-1])+32) + s[k:] s[:k-1] + chr(ord(s[k-1])+32) s[:k-1] s :k-1 k-1 k 1 chr(ord(s[k-1])+32) chr ord(s[k-1])+32 ord(s[k-1]) ord s[k-1] s k-1 k 1 32 s[k:] s k: k print(ans) print ans ans = s[:k-1] + chr(ord(s[k-1])+32) + s[k:] s[:k-1] + chr(ord(s[k-1])+32) + s[k:] ans n, k = map(int, input().split()) map(int, input().split()) n k = map(int, input().split()) map(int, input().split()) k s = input() input() s
n, k = map(int, input().split())
s = input()
ans = s[:k-1] + chr(ord(s[k-1])+32) + s[k:]
print(ans)