After the Blind Date, I Successfully Got Stuck in the Tiandao BUG

One, two, three, four, five, five on the left. One, two, three, four, four on the right. "Have you finished counting my tails?" The fox girl on the bed said dissatisfiedly, "Do you want to write a program to calculate the number of five plus four?" "Although I don't know what five plus four is equal to, but I know that five plus four is equal to four plus five," Chen Qiyuan responded, "because the addition of integers forms an Abelian group."