def gl
  $stdin.gets.chomp
end

N = gl.to_i
M = gl.to_i

scores = (0...M).map{ gl.split(" ").map{ |a| a.to_i } }
status = (0...M).map{ 0 }
(N-1).times {
  ns = (0...M).map{ |j| (0...M).map{ |i| scores[i][j] + status[i] }.max }
  status = ns
}
puts status.max