# ABC126
# A Changing a Character
n, k = map(int, input().split())
S = list(input())
x = S.pop(k-1).lower()
S.insert((k-1),x)
print("".join(S)) n, k = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split k S = list(input()) S list(input()) list input() input x = S.pop(k-1).lower() x S.pop(k-1).lower() S.pop(k-1).lower S.pop(k-1) S.pop S pop k-1 k 1 lower S.insert((k-1),x) S.insert S insert k-1 k 1 x print("".join(S)) print "".join(S) "".join "" join S k = map(int, input().split()) map(int, input().split()) k x = S.pop(k-1).lower() S.pop(k-1).lower() x n, k = map(int, input().split()) map(int, input().split()) n S = list(input()) list(input()) S
# ABC126
# A Changing a Character
n, k = map(int, input().split())
S = list(input())
x = S.pop(k-1).lower()
S.insert((k-1),x)
print("".join(S))
