Suppose Bob, a shopkeeper, has (square) tray of apples. While carrying tray he trips and drops apples all over floor. His assistant comes out of store room with the stack of 4 more trays. Clumsily he knocks edge of stack and row of apples from each of trays falls to floor. Given that the total number of apples on floor is 77 how many apples were on each tray to start?