Look the sentence with "!!!":
program p1048new;
var last,last2,n,p,q,s,i,j,k:longint;a:string;
begin
     readln(n);last2:=-1;j:=0;
     for i:=1 to n do begin
         readln(p,q);last:=p+q;
         if (last<9)and(last2<>-1) then begin
            if s=0 then begin
            write(last2);last2:=last;end;
            if s<>0 then begin
               write(last2);
        !!!!!!!! for j:=1 to s do write('9');!!!!!!!!
               s:=0;last2:=last;end;end;
         if last=9 then inc(s);
         if (last>9)and(last2<>-1) then begin
            if s=0 then begin
               write(last2+1);last2:=last mod 10;end;
            if s<>0 then begin
               if last2=9 then dec(s);
               write(last2+1);
              for j:=1 to s do write('0');
               s:=0;last2:=last mod 10;
               end;
               end;
         if last2=-1 then last2:=last;
     end;
     last:=last mod 10;
     if s=0 then write(last);
     if s<>0 then for i:=1 to s do write('9');
     readln;
end.