During his six grade summer vacation, xiaoxin got lots of watermelon candies from his leader when he did his internship at Tencent. Each watermelon candy has it's sweetness which denoted by an integer number.
xiaoxin is very smart since he was a child. He arrange these candies in a line and at each time before eating candies, he selects three continuous watermelon candies from a specific range [L, R] to eat and the chosen triplet must satisfies:
if he chooses a triplet $(a_i, a_j, a_k)$ then:
1. $j = i + 1, k = j + 1$
2. $a_i \leq a_j \leq a_k$
Your task is to calculate how many different ways xiaoxin can choose a triplet in range [L, R]?
two triplets $(a_0, a_1, a_2)$ and $(b_0, b_1, b_2)$ are thought as different if and only if:
$a_0 \neq b_0$ or $a_1 \neq b_1$ or $a_2 \neq b_2$