Untitled

uses crt;//xu ly so lon

//ham tinh tong 2 so lon
function sum(a,b:string):string;
var
    tong,nho,x,y,i:longint;
    c:string;
begin
    nho:=0;
    c:='';
    while (length(a)<length(b)) do a:='0'+a;
    while (length(b)<length(a)) do b:='0'+b; // a va b co do dai bang nhau
    for i:=length(a) downto 1 do
    begin
        x:=ord(a[i]) - ord('0');//so a[i]
        y:=ord(b[i]) - ord('0');//so b[i]
        tong:= x+y+nho;
        nho:=tong div 10;
        c:=chr(tong mod 10 +48)+c;
    end;
    if(nho>0) then c:='1'+c;
    sum:=c;
end;

//ham tinh hieu 2 so lon
function sub(a,b:string):string;
var
        c:string;
        i,hieu,nho:longint;
begin
    nho:=0;
    c:='';
    while(length(a)<length(b)) do a:='0'+a;
    while(length(b)<length(a)) do b:='0'+b; // a va b co do dai bang nhau
    for i:=length(a) downto 1 do
    begin
        hieu:=ord(a[i]) - ord(b[i]) -nho;
        if (hieu<0) then
        begin
            hieu:=hieu+10;
            nho:=1;
        end
        else    nho:=0;
        c:=chr(hieu+48)+c;
    end;
    while(length(c)>1) and (c[1]='0') do delete(c,1,1);
    sub:=c;
end;


var
  f:text;
  s1,s2,s3,s4:string;
begin
   clrscr;
   assign(f,'bai1.inp');reset(f);
   readln(f,s1);
   readln(f,s2);
   close(f);


   assign(f,'bai1.out');rewrite(f);
   //s3:=sum(s1,s2);
   s4:=sub(s1,s2);
   write(f,s4);close(f);
   //writeln(low(word));
   //writeln(high(word));



   readln;
end.