function enter() {
    if (msg.value != 1 ether) { 
        msg.sender.send(msg.value);
        return;
    }
   
    uint transactionAmount;
    uint k = 0;

    
    uint total_inv = benefactor.length;
    benefactor.length += 1;
    benefactor[total_inv].etherAddress = msg.sender;
    benefactor[total_inv].amount = msg.value;

	balance += msg.value;  

   
    while (k<total_inv) 
    { 
    	transactionAmount = msg.value * benefactor[k].amount / totalBalance;       
		benefactor[k].etherAddress.send(transactionAmount);    					
		balance -= transactionAmount;                        					
        k += 1; 
    }
    
	totalBalance += msg.value;  
    
    
  }