n, k = map(int,input().split())
s = input()
print(s[:k - 1], end = '')
print(str.swapcase(s[k - 1]), end = '')
print(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 print(s[:k - 1], end = '') print s[:k - 1] s :k - 1 k - 1 k 1 end = '' end '' print(str.swapcase(s[k - 1]), end = '') print str.swapcase(s[k - 1]) str.swapcase str swapcase s[k - 1] s k - 1 k 1 end = '' end '' print(s[k:]) print s[k:] s k: k n, k = map(int,input().split()) map(int,input().split()) n k = map(int,input().split()) map(int,input().split()) k s = input() input() s
n, k = map(int,input().split())
s = input()
print(s[:k - 1], end = '')
print(str.swapcase(s[k - 1]), end = '')
print(s[k:])