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

first = s[:k-1]
mid = s[k-1].lower()
last = s[k:]

print( first + mid + last ) n, k = list(map(int, input().split())) n list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split k s = input() s input() input first = s[:k-1] first s[:k-1] s :k-1 k-1 k 1 mid = s[k-1].lower() mid s[k-1].lower() [k-1].lower [k-1] s k-1 k 1 lower last = s[k:] last s[k:] s k: k print( first + mid + last ) print first + mid + last first + mid first mid last last = s[k:] s[k:] last n, k = list(map(int, input().split())) list(map(int, input().split())) n k = list(map(int, input().split())) list(map(int, input().split())) k s = input() input() s mid = s[k-1].lower() s[k-1].lower() mid first = s[:k-1] s[:k-1] first
n, k = list(map(int, input().split()))
s = input()

first = s[:k-1]
mid = s[k-1].lower()
last = s[k:]

print( first + mid + last )
