n,k = [int(x) for x in input().split()]
s = input()
 
k -= 1
s = list(s)

if s[k] == "A":
  s[k] = "a"
elif s[k] == "B":
  s[k] = "b"
elif s[k] == "C":
  s[k] = "c"
 
print("".join(s)) int(x) for x in input().split() for x in input().split() x input().split() ().split () input split for x in input().split() int(x) int x n,k = [int(x) for x in input().split()] n [int(x) for x in input().split()] k s = input() s input() input k -= 1 k 1 s = list(s) s list(s) list s if s[k] == "A":
  s[k] = "a"
elif s[k] == "B":
  s[k] = "b"
elif s[k] == "C":
  s[k] = "c"
  s[k] == "A" s[k] s k "A" s[k] = "a" s[k] s k "a" elif s[k] == "B":
  s[k] = "b" s[k] == "B" s[k] s k "B" s[k] = "b" s[k] s k "b" elif s[k] == "C":
  s[k] = "c"
  s[k] == "C" s[k] s k "C" s[k] = "c" s[k] s k "c" print("".join(s)) print "".join(s) "".join "" join s s = input() input() s k = [int(x) for x in input().split()] [int(x) for x in input().split()] k k -= 1 1 k s = list(s) list(s) s n,k = [int(x) for x in input().split()] [int(x) for x in input().split()] n
n,k = [int(x) for x in input().split()]
s = input()
 
k -= 1
s = list(s)

if s[k] == "A":
  s[k] = "a"
elif s[k] == "B":
  s[k] = "b"
elif s[k] == "C":
  s[k] = "c"
 
print("".join(s))