N,K = map(int,input().split())
moji = str(input())
ans = moji[:K-1] + moji[K-1].lower() + moji[K:]
print(ans) N,K = map(int,input().split()) N map(int,input().split()) map int input().split() ().split () input split K moji = str(input()) moji str(input()) str input() input ans = moji[:K-1] + moji[K-1].lower() + moji[K:] ans moji[:K-1] + moji[K-1].lower() + moji[K:] moji[:K-1] + moji[K-1].lower() moji[:K-1] moji :K-1 K-1 K 1 moji[K-1].lower() [K-1].lower [K-1] moji K-1 K 1 lower moji[K:] moji K: K print(ans) print ans ans = moji[:K-1] + moji[K-1].lower() + moji[K:] moji[:K-1] + moji[K-1].lower() + moji[K:] ans K = map(int,input().split()) map(int,input().split()) K N,K = map(int,input().split()) map(int,input().split()) N moji = str(input()) str(input()) moji
N,K = map(int,input().split())
moji = str(input())
ans = moji[:K-1] + moji[K-1].lower() + moji[K:]
print(ans)