There is a sequence of N + 2 elements a₀, a₁, …, a_N+1 (1 ≤ N ≤ 3000, −2000 ≤ a_i ≤ 2000). It is known that

for each i = 1, 2, …, N.

You are given a₀, a_N+1, c₁, …, c_N. Write a program which calculates a₁.

The first line contains an integer N. The next two lines consist of numbers a₀ and a_N+1 each having two digits after decimal point, and the next N lines contain numbers c_i (also with two digits after decimal point), one number per line.

Output a₁ in the same format as a₀ and a_N+1.