#1
puts gets.chomp.split(//).each_with_index.select{|c,i| i.even?}.map{|c| c[0]}.join

#2
out = Array.new(7,0)
puts gets.to_i.times.map{|i| out[i%7] += gets.to_i}[-7..-1]

#MINAMI
x, y = gets.split.map(&:to_i)
y.times.map{gets.split.map(&:to_i)}.transpose.map{|r| [1] * r.count(1) + [0] * (y - r.count(1))}.transpose.reverse.map{|r| puts r * " "}

#RENA
x, y, N = gets.split.map(&:to_i)
t = y.times.map{gets.split.map(&:to_i)}
s = N.times.map{gets.split.map(&:to_i)}
ans = 0
t.each.with_index(1) do |r,i|
    r.each.with_index(1) do |c,j|
        s.each do |xs,ys,xe,ye|
            if i.between?(ys,ye) && j.between?(xs,xe)
                ans += c
                break
            end
        end
    end
end
p ans