N,K=map(int,input().split())
S=input()
S = S[:K-1] + chr(ord(S[K-1])+32) + S[K:]
print(S) N,K=map(int,input().split()) N map(int,input().split()) map int input().split() ().split () input split K S=input() S input() input S = S[:K-1] + chr(ord(S[K-1])+32) + S[K:] S S[:K-1] + chr(ord(S[K-1])+32) + S[K:] S[:K-1] + chr(ord(S[K-1])+32) S[:K-1] S :K-1 K-1 K 1 chr(ord(S[K-1])+32) chr ord(S[K-1])+32 ord(S[K-1]) ord S[K-1] S K-1 K 1 32 S[K:] S K: K print(S) print S S = S[:K-1] + chr(ord(S[K-1])+32) + S[K:] S[:K-1] + chr(ord(S[K-1])+32) + S[K:] S K=map(int,input().split()) map(int,input().split()) K N,K=map(int,input().split()) map(int,input().split()) N S=input() input() S
N,K=map(int,input().split())
S=input()
S = S[:K-1] + chr(ord(S[K-1])+32) + S[K:]
print(S)