N,K = map(int,input().split())
S = str(input())
T = list(map(str,S))

for i in range(N):
    if i == K-1:
        T[i] = str.lower(T[i])

print("".join(T)) 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 T = list(map(str,S)) T list(map(str,S)) list map(str,S) map str S for i in range(N):
    if i == K-1:
        T[i] = str.lower(T[i]) i range(N) range N if i == K-1:
        T[i] = str.lower(T[i]) i == K-1 i K-1 K 1 T[i] = str.lower(T[i]) T[i] T i str.lower(T[i]) str.lower str lower T[i] T i print("".join(T)) print "".join(T) "".join "" join T S = str(input()) str(input()) S N,K = map(int,input().split()) map(int,input().split()) N K = map(int,input().split()) map(int,input().split()) K T = list(map(str,S)) list(map(str,S)) T
N,K = map(int,input().split())
S = str(input())
T = list(map(str,S))

for i in range(N):
    if i == K-1:
        T[i] = str.lower(T[i])

print("".join(T))