THE RESULT IS WRONG ANSWER INSTEAD OF MEMORY LIMIT EXCEED
SEE THIS:
var
  a , b : array [1..1000002] of byte;
  i , n : longint;
procedure jia;
var
  p : integer;
begin
  for p := 1 to n do begin
    b[p] := a[p] + b[p];
  end;
  for p := 1 to n+2 do begin
    b[p+1] := b[p+1] + b[p] div 10;
    b[p] := b[p] mod 10;
  end;
end;
procedure out;
var
  ws : longint;
begin
  ws := n+5;
  if ws > 1000001 then ws := 1000001;
  while (b[ws]=0) and (ws<>1) do dec(ws);
  for i := ws downto 1 do
    write(b[i]);
  writeln;
end;

begin
  readln(n);
  for i := 1 to n do
    readln(a[n-i+1],b[n-i+1]);
  jia;
  out;
end.

> THE RESULT IS WRONG ANSWER INSTEAD OF MEMORY LIMIT EXCEED
> SEE THIS:
> var
>   a , b : array [1..1000002] of byte;
>   i , n : longint;
> procedure jia;
> var
>   p : integer;
> begin
>   for p := 1 to n do begin
>     b[p] := a[p] + b[p];
>   end;
>   for p := 1 to n+2 do begin
>     b[p+1] := b[p+1] + b[p] div 10;
>     b[p] := b[p] mod 10;
>   end;
> end;
> procedure out;
> var
>   ws : longint;
> begin
>   ws := n+5;
>   if ws > 1000001 then ws := 1000001;
>   while (b[ws]=0) and (ws<>1) do dec(ws);
>   for i := ws downto 1 do
>     write(b[i]);
>   writeln;
> end;
>
> begin
>   readln(n);
>   for i := 1 to n do
>     readln(a[n-i+1],b[n-i+1]);
>   jia;
>   out;
> end.
>
>
>

I think:
1) you should submit an online solution. I really don't know why it
doesn't get an ML.
2) this solution is wrong. Read the problem text:
Output file should contain EXACTLY N DIGITS in a single line
representing the sum of these two integers,
and then run the following:
4
0 0
0 0
0 0
0 0
The answer must be 0000, but you output 0.