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

           
if(S[K-1] == "A"):
  S[K-1] = "a"
elif(S[K-1] == "B"):
  S[K-1] = "b"
elif(S[K-1] == "C"):
  S[K-1] = "c"
           
"".join(S)

S_1 = S[0]
for i in range(1,N):
  S_1 = S_1 + S[i]
print(S_1) N, K = map(int, input().split()) N map(int, input().split()) map int input().split() ().split () input split K S = list(input()) S list(input()) list input() input if(S[K-1] == "A"):
  S[K-1] = "a"
elif(S[K-1] == "B"):
  S[K-1] = "b"
elif(S[K-1] == "C"):
  S[K-1] = "c"
            S[K-1] == "A" S[K-1] S K-1 K 1 "A" S[K-1] = "a" S[K-1] S K-1 K 1 "a" elif(S[K-1] == "B"):
  S[K-1] = "b" S[K-1] == "B" S[K-1] S K-1 K 1 "B" S[K-1] = "b" S[K-1] S K-1 K 1 "b" elif(S[K-1] == "C"):
  S[K-1] = "c"
            S[K-1] == "C" S[K-1] S K-1 K 1 "C" S[K-1] = "c" S[K-1] S K-1 K 1 "c" "".join(S) "".join "" join S S_1 = S[0] S_1 S[0] S 0 for i in range(1,N):
  S_1 = S_1 + S[i] i range(1,N) range 1 N S_1 = S_1 + S[i] S_1 S_1 + S[i] S_1 S[i] S i print(S_1) print S_1 K = map(int, input().split()) map(int, input().split()) K S_1 = S[0] S[0] S_1 S = list(input()) list(input()) S S_1 = S_1 + S[i] S_1 + S[i] S_1 N, K = map(int, input().split()) map(int, input().split()) N
N, K = map(int, input().split())
S = list(input())

           
if(S[K-1] == "A"):
  S[K-1] = "a"
elif(S[K-1] == "B"):
  S[K-1] = "b"
elif(S[K-1] == "C"):
  S[K-1] = "c"
           
"".join(S)

S_1 = S[0]
for i in range(1,N):
  S_1 = S_1 + S[i]
print(S_1)
