n, k = map(int, input().split())
s = input()

ABC = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
abc = 'abcdefghijklmnopqrstuvwxyz'
print(s[:k-1] + abc[ABC.index(s[k-1])] + s[k:]) n, k = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split k s = input() s input() input ABC = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' ABC 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' abc = 'abcdefghijklmnopqrstuvwxyz' abc 'abcdefghijklmnopqrstuvwxyz' print(s[:k-1] + abc[ABC.index(s[k-1])] + s[k:]) print s[:k-1] + abc[ABC.index(s[k-1])] + s[k:] s[:k-1] + abc[ABC.index(s[k-1])] s[:k-1] s :k-1 k-1 k 1 abc[ABC.index(s[k-1])] abc ABC.index(s[k-1]) ABC.index ABC index s[k-1] s k-1 k 1 s[k:] s k: k ABC = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' ABC abc = 'abcdefghijklmnopqrstuvwxyz' 'abcdefghijklmnopqrstuvwxyz' abc n, k = map(int, input().split()) map(int, input().split()) n s = input() input() s k = map(int, input().split()) map(int, input().split()) k
n, k = map(int, input().split())
s = input()

ABC = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
abc = 'abcdefghijklmnopqrstuvwxyz'
print(s[:k-1] + abc[ABC.index(s[k-1])] + s[k:])