John likes simple ciphers. He had been using the “Caesar” cipher to encrypt his diary until recently, when he learned a hard lesson about its strength by catching his sister Mary browsing through the diary without any problems.
Rapidly searching for an alternative, John found the famous “Autokey” cipher. He uses a version that takes the lower-case letters a--z and internally translates them in alphabetical order to the numbers to .
The encryption key begins with a secret prefix of letters. Each of the remaining letters of the key is copied from the letters of the plaintext , so that for . Encryption of the plaintext to the ciphertext follows the formula .
Mary was able to get a peek at the last letters John typed before he noticed her, encrypted the text document, and left. This could be her chance.
输入格式
The input consists of:
One line with two integers and (, ), where is the keyword length as well as the number of letters Mary saw, and is the length of the text.
One line with lower-case letters, the last letters of the plaintext.
One line with lower-case letters, the whole ciphertext.
