exp

Two sequences of n positive integers, x₁, …, x_n, and respectively y₁, …, y_n and a sequence of n numerical operators from group {+, -} s₁, …, s_n are given.

Task

Determine the maximum value of expression:
s₁c₁·d₁s₂c₂·d₂ … s_n-1c_n-1·d_n-1s_nc_n·d_n
where c_i is a digit of x_i, and d_i is a digit of y_i, for i=1, 2, …, n.

Input Data

Input file exp.in contains on the first line the positive integer n, on the second line operators s₁, …, s_n, without any space in between, and on each of the following n lines a pair of positive integers in the form of x_i y_i, i=1, 2, …, n, each separated by a space.

Output Data

Output file exp.out will contain a single line with the maximum value of the expression.

Constraints and Statements

• 0 < n <= 64000
• The numbers x₁, …, x_n, y₁, …, y_n have at most 9 digits.
  

Time limit: 0.2 seconds/test

prof. Doru Popescu Anastasiu
"Radu Greceanu" Slatina National High School
Contact:dopopan@yahoo.com