program alex;
var f,g:text;
    p,h,j,i,d:longint;
begin
assign(f,'fact.in');reset(f);
readln(f,p);
close(f);
assign(g,'fact.out');rewrite(g);
if p=0 then write(g,1)
       else begin
            i:=5;
            j:=1;
            repeat
            h:=j*i;
            while(h mod 5=0)do
                  begin
                  h:=h div 5;
                  d:=d+1;
                  end;
            j:=j+1;
            until d>=p;
            if d=p then write(g,i*j)
                   else write(g,i*j-5);
            end;
close(g);
end.