program pd;
var n,k,i,m,j,a,b:integer;
zag:array[1..1000,1..1000] of integer;
lef:array[1..1000,1..1000] of integer;
rez:array[1..1000,1..1000] of integer;
q,w:text;

begin

assign(q,'d:\legacy.in');
assign(w,'d:\legacy.out');
reset(q);
rewrite(w);
read(q,n,m);


for i:=1 to n do begin readln(q,rez[i,j]); end;
for j:=1 to n-1 do begin read(q,rez[j,i]); end;

for j:=1 to n do
k:=rez[1,1]+rez[1,2]+rez[2,1]+rez[2,2];

write(w,k);
close(q);
close(w);
end.