var f,g:text;
    j,p,i,nr:longint;
begin
    assign(f,'fact.in'); reset(f);
    assign(g,'fact.out'); rewrite(g);
    readln(f,p);
    i:=0; nr:=0;
    if p=0
       then writeln(g,'1')
       else
          begin
             while nr<p do
                begin
                   inc(i,5); j:=i;
                   while j mod 5=0 do
                      begin
                         inc(nr);
                         j:=j div 5;
                      end;
                end;
             if nr=p then writeln(g,i) else writeln(g,'-1');
          end;
    close(f); close(g);
end.