function claim_bounty(){
    
    if (bought_tokens) return;
    
    if (kill_switch) return;
    
    if (now < earliest_buy_time) return;
    
    if (sale == 0x0) throw;
    
    bought_tokens = true;
    
    time_bought = now;
    
    
    
    if(!sale.call.value(this.balance - bounty)()) throw;
    
    msg.sender.transfer(bounty);
  }