Type bigNum = ansistring; 

function multiply1(a:bigNum;b:longint):bigNum;
var i :integer;
 carry,s :longint;
 c,tmp :bigNum;
 begin
 c:='';
 carry:=0;
 for i:=length(a) downto 1 do
 begin
 s:=(ord(a[i])-48) * b + carry;
 carry:= s div 10;
 c:=chr(s mod 10 + 48)+c;
 end;
 if carry>0 then str(carry,tmp) else tmp:='';
 multiply1:=tmp+c;
 end; 

function multiply2(a,b:bigNum):bigNum;
var sum,tmp :bigNum;
m,i,j :integer;
begin
m:=-1;sum:='';
for i:=length(a) downto 1 do
begin
m:=m+1;
tmp:=multiply1(b,ord(a[i])-48);
for j:=1 to m do tmp:=tmp+'0';
sum:=add(tmp,sum);
 end;
exit(sum);
end; 

Program so_lon;
 var
  st,st1,st2:string;
 Function Cong(s1,s2:String):String;
Var
    L1,L2,Max,i,tam,a,b,code,nho:Integer;
    h,h1:String;
Begin
 L1:=length(s1);
 L2:=length(s2);
if L1>L2 Then Max:=L1 Else Max:=L2;
 For i:=L1+1 to Max do s1:='0'+s1;
For i:=L2+1 to Max do s2:='0'+s2;
nho:=0; h:='';
For i:=Max downto 1 do
   Begin
       val(s1[i],a,code);
       val(s2[i],b,code);
       tam:=a+b+nho;
if tam>=10 Then nho:=1  Else nho:=0;
  str(tam Mod 10,h1);
h:=h1+h; End;
if nho=1 Then h:='1'+h;
cong:=h;
 End;
 Begin
  write('nhap so thu nhat'); readln(st1);
  write('nhap so thu hai'); readln(st2);
  writeln('ket qua la', cong(st1,st2));
  readln;
 End.