program main_long;
var a,b,c:array[0..1000] of integer;
i:integer;
f:text;
ch:char;
ost:integer;
begin
assign(f,'long.dat');
reset(f);
for i:=0 to 1000 do a[i]:=0;
while not(eoln(f)) do begin
read(f,ch);
if ch in ['0'..'9'] then begin
for i:=a[0] downto 1 do a[i+1]:=a[i];
a[0]:=a[0]+1;
a[1]:=ord(ch)-ord('0');
end;
end;
for i:=0 to 1000 do b[i]:=0;
while not(eof(f)) do begin
read(f,ch);
if ch in ['0'..'9'] then begin
for i:=b[0] downto 1 do b[i+1]:=b[i];
b[0]:=b[0]+1;
b[1]:=ord(ch)-ord('0');
end;
end;
close (f);
if a[0]>b[0] then c[0]:=a[0] else c[0]:=b[0];
for i:=1 to c[0] do begin
if a[i]>b[i] then c[i]:=a[i]-b[i] else c[i]:=10+a[i]-b[i];
end;
assign(f,'long.sol');
rewrite(f);
WHILE C[c[0]]=0 do c[0]:=c[0]-1;
FOR i:=c[0] downto 1 do write(f,c[i]);
close(f);

end.