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

S[k-1] = S[k-1].lower() 
S = "".join(S)
print(S) N, k = input().split() N input().split() ().split () input split k N = int(N) N int(N) int N k = int(k) k int(k) int k S = input() S input() input S = list(S) S list(S) list S S[k-1] = S[k-1].lower() S[k-1] S k-1 k 1 S[k-1].lower() [k-1].lower [k-1] S k-1 k 1 lower S = "".join(S) S "".join(S) "".join "" join S print(S) print S k = input().split() input().split() k k = int(k) int(k) k S = list(S) list(S) S S = input() input() S N = int(N) int(N) N N, k = input().split() input().split() N S = "".join(S) "".join(S) S
N, k = input().split()
N = int(N)
k = int(k)
S = input()
S = list(S)

S[k-1] = S[k-1].lower() 
S = "".join(S)
print(S)