var p,n,r,c:int64;
f,g:text;
begin
assign(f,'fact.in');reset(f);
assign(g,'fact.out');rewrite(g);
read(f,p);
if p+1 mod 6 =0 then write(g,'-1')
else
begin
c:=p div 6;
r:=p mod 6;
n:=c*25+r*5;
write(g,n);
end;
close(g);
close(f);
end.