program z2_53;
var i,j,k:integer; z,st:string;
t:text;
begin
assign(t,'h:\text.txt');
rewrite(t);
k:=0; readln(z);
for I:=1 to 9 do
for j:=1 to 9 do begin
k:=i*10+j; write(t,k);end;
close(t); reset(t);
while not(eof(t)) do begin readln(t,st);
writeln(st);K:=pos(z,st);end;
writeln(k div 2);close(t);
end.