Word Dealer

Sonny the robot can only speak words that he has stored in his memory.But he has now run out of memory space and he has to forget a word to learn a new word. So, he goes to the Word Dealer who takes the word he knows and gives him the word he wants for a price. The price is determined by a 26 x 26 matrix containing non-negative entries. The entry (i , j) denotes the cost of replacing the ith alpha