program factorial;
var f,g:text;
nrzero,p,i,j:longint;
begin
assign(f,'fact.in');
reset(f);
assign(g,'fact.out');
rewrite(g);
readln(f,p);
close(f);
i:=0;
j:=0;
nrzero:=0;
if p=0 then begin
writeln(g,1);
close(g);
exit;
end;
i:=0;
while i<100000000 do begin
i:=i+5;
j:=i;
while j<>0 do begin
if j mod 5=0 then inc(nrzero);
j:=j div 5;
end;
if p<= nrzero then begin
if p=nrzero then writeln(g,i)else if p<nrzero then writeln(g,-1);
close(g);
halt;
end;
end;
end.