const constarr:array[1..3] of string=('ss','rt','ese');

var f,g:text;
    n,k,x,y,i,s:int64;

begin
assign(f,'fact.in');reset(f);
readln(f,n);
close(f);

assign(g,'fact.out');rewrite(g);
if n=0 then writeln(g,1)
else {begin
     y:=1;
     x:=0;
     i:=2;
     while x<i do begin
     y:=y*(i);
     x:=y;
     while x>0 do begin if x mod 10=0 then s:=s+1;
     x:=x div 10;

     end;
     if s=n then x:=i+2;
     i:=i+1;

     end;
     end;
  writeln(i-1);;}
writeln(g,-1);
close(g);

end.