n, k = map(int, input().split())
s = input()
for c in range(n):
  if c == k-1:
    print(s[c].lower(), end="")
  else:
    print(s[c], end="") n, k = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split k s = input() s input() input for c in range(n):
  if c == k-1:
    print(s[c].lower(), end="")
  else:
    print(s[c], end="") c range(n) range n if c == k-1:
    print(s[c].lower(), end="")
  else:
    print(s[c], end="") c == k-1 c k-1 k 1 print(s[c].lower(), end="") print s[c].lower() [c].lower [c] s c lower end="" end "" print(s[c], end="") print s[c] s c end="" end "" s = input() input() s n, k = map(int, input().split()) map(int, input().split()) n k = map(int, input().split()) map(int, input().split()) k
n, k = map(int, input().split())
s = input()
for c in range(n):
  if c == k-1:
    print(s[c].lower(), end="")
  else:
    print(s[c], end="")