Periodic Function (Easy)

This problem has different input constraints from Periodic Function (Hard).

A periodic function is a function whose values repeat at regular intervals. Formally, if there is a positive number $p$ such that $f(x+p)=f(x)$ for all $x$, then $f(x)$ is called a periodic function, and $p$ is called a period. A single function can have several periods. For example, if $f(x) = \sin x$, then $2n\pi$ is a period for every positive integer $n$.

Periodic functions make definite integrals easier to compute, because shifting the interval by one period does not change the value. For example, the period of $\sin$ is $2\pi$, so $\int_0^\pi \sin x\,dx = \int_{2\pi}^{3\pi} \sin x\,dx$.

Every day, Dooyoung brings Ian a periodic function that Ian has never seen. Dooyoung gives the integral over an interval whose length equals the period, and asks Ian to find the integral over another interval. Tired of solving these by hand, Ian wants a program that computes the answers automatically.

The first line contains the period $p$ of the function.

The second line contains $p$ integers separated by spaces. For $1 \le i \le p$, the $i$-th number is $\int_{i-1}^i f(x)\,dx$.

The third line contains two integers $a$ and $b$ separated by a space, the endpoints of the interval to find.

Print the value of $\int_a^b f(x)\,dx$ on one line.

• $1 \le p \le 10^5$
• $-10^9 \le a \le b \le 10^9$
• The absolute value of every integral is at most $10^9$.
• All input values are integers.