N, K = map(int,input().split())
S = input()
ans = []
for i in range(N):
    if i == K - 1:
        x = ord(S[i])
        x += 32
        y = chr(x)
        ans.append(y)
    else:
        ans.append(S[i])

print(''.join(ans)) N, K = map(int,input().split()) N map(int,input().split()) map int input().split() ().split () input split K S = input() S input() input ans = [] ans [] for i in range(N):
    if i == K - 1:
        x = ord(S[i])
        x += 32
        y = chr(x)
        ans.append(y)
    else:
        ans.append(S[i]) i range(N) range N if i == K - 1:
        x = ord(S[i])
        x += 32
        y = chr(x)
        ans.append(y)
    else:
        ans.append(S[i]) i == K - 1 i K - 1 K 1 x = ord(S[i]) x ord(S[i]) ord S[i] S i x += 32 x 32 y = chr(x) y chr(x) chr x ans.append(y) ans.append ans append y ans.append(S[i]) ans.append ans append S[i] S i print(''.join(ans)) print ''.join(ans) ''.join '' join ans x += 32 32 x K = map(int,input().split()) map(int,input().split()) K N, K = map(int,input().split()) map(int,input().split()) N ans = [] [] ans x = ord(S[i]) ord(S[i]) x y = chr(x) chr(x) y S = input() input() S
N, K = map(int,input().split())
S = input()
ans = []
for i in range(N):
    if i == K - 1:
        x = ord(S[i])
        x += 32
        y = chr(x)
        ans.append(y)
    else:
        ans.append(S[i])

print(''.join(ans))