N = list(map(int,input().split()))
S = list(input())


for i in range(len(S)):
  if i+1 == N[1]:
    print(str.lower(S[N[1]-1]),end="")
  else:
  	print(S[i],end="") N = list(map(int,input().split())) N list(map(int,input().split())) list map(int,input().split()) map int input().split() ().split () input split S = list(input()) S list(input()) list input() input for i in range(len(S)):
  if i+1 == N[1]:
    print(str.lower(S[N[1]-1]),end="")
  else:
  	print(S[i],end="") i range(len(S)) range len(S) len S if i+1 == N[1]:
    print(str.lower(S[N[1]-1]),end="")
  else:
  	print(S[i],end="") i+1 == N[1] i+1 i 1 N[1] N 1 print(str.lower(S[N[1]-1]),end="") print str.lower(S[N[1]-1]) str.lower str lower S[N[1]-1] S N[1]-1 N[1] N 1 1 end="" end "" print(S[i],end="") print S[i] S i end="" end "" N = list(map(int,input().split())) list(map(int,input().split())) N S = list(input()) list(input()) S
N = list(map(int,input().split()))
S = list(input())


for i in range(len(S)):
  if i+1 == N[1]:
    print(str.lower(S[N[1]-1]),end="")
  else:
  	print(S[i],end="")
