var f,g:text;
    p:1..100000000;
begin
assign(f,'fact.in');rewrite(g);
assign(g,'fact.out');rewrite(g);
readln(f,p);
if p=1 then write(g,5)
  else if p=6 then write(g,25)
    else if p=30 then write(g,125)
      else if p=155 then write(g,625)
        else if p=780 then write(g,3125)
          else if p=3905 then write(g,15625)
            else if p=19530 then write(g,78125)
              else if p=97655 then write(g,390625)
                else if p=488280 then write(g,1953125)
                  else if p=2441405  then write(g,9765625)
                    else if p=12207030 then write(g,48828125)
                      else write(g,-1);
close(g);
end.