var f:text;
    p,i,n,aux,put:longint;
begin
assign(f,'fact.in');
reset(f);
read(f,p);
close(f);
assign(f,'fact.out');
rewrite(f);
if p=0 then begin write(f,1);
                  close(f);
                  halt;
            end
       else
if p=1 then begin write(f,5);
                  close(f);
                  halt;
            end
        else
begin i:=1;{nr de 0}
      n:=5;
      while i<p do
       begin n:=n+5;
             aux:=n;   put:=0;
             while aux mod 5=0 do
             begin inc(put);
               aux:=aux div 5;
              end;
             if put>0 then i:=i+put;
       end;
end;
write(f,n);
close(f);
end.