n,k=map(int,input().split())
S=input()
s=str.lower(S[k-1])
ans=S[:k-1]+s+S[k:]
print(ans) 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=str.lower(S[k-1]) s str.lower(S[k-1]) str.lower str lower S[k-1] S k-1 k 1 ans=S[:k-1]+s+S[k:] ans S[:k-1]+s+S[k:] S[:k-1]+s S[:k-1] S :k-1 k-1 k 1 s S[k:] S k: k print(ans) print ans ans=S[:k-1]+s+S[k:] S[:k-1]+s+S[k:] ans k=map(int,input().split()) map(int,input().split()) k S=input() input() S n,k=map(int,input().split()) map(int,input().split()) n s=str.lower(S[k-1]) str.lower(S[k-1]) s
n,k=map(int,input().split())
S=input()
s=str.lower(S[k-1])
ans=S[:k-1]+s+S[k:]
print(ans)