N, K = map(int,input().split())
S = input()
a = S[:K-1] + str.lower(S[K-1]) + S[K:]
print(a) N, K = map(int,input().split()) N map(int,input().split()) map int input().split() ().split () input split K S = input() S input() input a = S[:K-1] + str.lower(S[K-1]) + S[K:] a S[:K-1] + str.lower(S[K-1]) + S[K:] S[:K-1] + str.lower(S[K-1]) S[:K-1] S :K-1 K-1 K 1 str.lower(S[K-1]) str.lower str lower S[K-1] S K-1 K 1 S[K:] S K: K print(a) print a S = input() input() S K = map(int,input().split()) map(int,input().split()) K a = S[:K-1] + str.lower(S[K-1]) + S[K:] S[:K-1] + str.lower(S[K-1]) + S[K:] a N, K = map(int,input().split()) map(int,input().split()) N
N, K = map(int,input().split())
S = input()
a = S[:K-1] + str.lower(S[K-1]) + S[K:]
print(a)