require "bigdecimal"

while line=gets
    cod=line.chomp.split(" ").map{|x| BigDecimal(x)}
    if (cod[0]-cod[2])*(cod[4]-cod[6])+(cod[1]-cod[3])*(cod[5]-cod[7])==BigDecimal("0.0") then
        puts "YES"
    else
        puts "NO"
    end
end