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

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

for i in range(N):
    if i == K-1:
        a=S[i].lower()
        S[i]=a
print(''.join(S))