N,K = map(int,input().split())
S = input()
s = list(S)
T = s[K-1]
T = T.lower()
s[K-1] = T
s = ''.join(s)
print(s) 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 = list(S) s list(S) list S T = s[K-1] T s[K-1] s K-1 K 1 T = T.lower() T T.lower() T.lower T lower s[K-1] = T s[K-1] s K-1 K 1 T s = ''.join(s) s ''.join(s) ''.join '' join s print(s) print s N,K = map(int,input().split()) map(int,input().split()) N s = list(S) list(S) s T = s[K-1] s[K-1] T T = T.lower() T.lower() T s = ''.join(s) ''.join(s) s S = input() input() S K = map(int,input().split()) map(int,input().split()) K
N,K = map(int,input().split())
S = input()
s = list(S)
T = s[K-1]
T = T.lower()
s[K-1] = T
s = ''.join(s)
print(s)