n,k = map(int, input().split())
s = input()
s_s = s[:k-1]
s_l = s[k-1].lower()
s_e = s[k:]
print(s_s+s_l+s_e) 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 = s[:k-1] s_s s[:k-1] s :k-1 k-1 k 1 s_l = s[k-1].lower() s_l s[k-1].lower() [k-1].lower [k-1] s k-1 k 1 lower s_e = s[k:] s_e s[k:] s k: k print(s_s+s_l+s_e) print s_s+s_l+s_e s_s+s_l s_s s_l s_e s = input() input() s s_s = s[:k-1] s[:k-1] s_s n,k = map(int, input().split()) map(int, input().split()) n s_l = s[k-1].lower() s[k-1].lower() s_l s_e = s[k:] s[k:] s_e k = map(int, input().split()) map(int, input().split()) k
n,k = map(int, input().split())
s = input()
s_s = s[:k-1]
s_l = s[k-1].lower()
s_e = s[k:]
print(s_s+s_l+s_e)