i,t,j,ch:longint;

s1,s:string;

begin

readln(s);

i:=pos(' ',s);

s1:=copy(s,1,i-1);

delete(s,1,i);

t:=0;

for i:=1 to length(s1) do

begin

ch:=ord(s1[i])-ord('0');

for j:=1 to length(s) do

t:=t+ch*(ord(s[j])-ord('0'));

end;

writeln(t);

end.