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