contract.sol

pragma solidity ^0.4.20;

contract Store {
	address private owner;

	modifier onlyOwner() {
		require(msg.sender == owner);
		_;
	}

	function Store() public {
		owner = msg.sender;
	}

	function deposit() public payable onlyOwner {
	}

	function withdraw(address to, uint value) public onlyOwner {
		to.transfer(value);
	}
}

contract Main {
	mapping(address => mapping(address => uint)) public allowed;
	Store private store;

	function Main() public {
		store = new Store();
	}

	function send(address to) public payable {
		require(msg.value > 0);
		allowed[msg.sender][to] += msg.value;
		store.deposit.value(msg.value)();
	}

	function receive(address from, uint amount) public {
		require(allowed[from][msg.sender] >= amount && amount > 0);
		allowed[from][msg.sender] -= amount;
		store.withdraw(msg.sender, amount);
	}

	function takeBack(address from, uint amount) public {
		require(allowed[msg.sender][from] >= amount && amount > 0);
		allowed[msg.sender][from] -= amount;
		store.withdraw(msg.sender, amount);
	}
}