program factorial;
var f,g:text;                               {1 cifra de 0... 1*2*3*4*5}
    i,p,gasit,nr,i1:longint;                {4 cifre de 0 ... 5*..10*..15..20}
begin
     assign(f,'fact.in');
     assign(g,'fact.out');
     reset(f);
     rewrite(g);
     read(f,p);
     gasit:=0;
     i:=0;
     if p=0 then nr:=1;
     while(gasit<p) do
     begin
          i:=i+5;
          i1:=i;
          {cautam toti divizorii de 5,
          adica de cate ori se imparte la 5 produsul nostru,
          mergem din 5 in 5 cu cautarea 5,10, 15.....}
          while (i1 mod 5=0) do
          begin
               i1:=i1 div 5;
               gasit:=gasit+1;
          end;

     end;
     nr:=i;
     write(g,nr);
     close(f);
     closE(g);
end.