function tokenGenerationEvent(address _participant) payable external {
        require( ( whitelistContributor[_participant] || whitelistContributor[msg.sender] || balances[_participant] > 0 || kycRequirement )  && !allSaleCompleted && ( block.timestamp <= end_time ) && msg.value > 0);
    
        uint256 rate = 1000;  
        rate = safeDiv( 175 * 10**5 * 10**decimals, safeAdd( 875 * 10**1 * 10**decimals, safeDiv( totalTokens, 2 * 10**3)) );
        if ( rate > 2000 ) rate = 2000;
        if ( rate < 500 ) rate = 500;
        require(block.number >= start_block) ;

        uint256 tokens = safeMul(msg.value, rate);
        uint256 checkedSupply = safeAdd(totalTokens, tokens);
        require(checkedSupply <= tokenGenerationMax);

        totalTokens = checkedSupply;
        contributorTokens = safeAdd(contributorTokens, tokens);
        
        Transfer(address(this), _participant, tokens);
        balances[_participant] = safeAdd(balances[_participant], tokens);
        contribution[_participant] = safeAdd(contribution[_participant], msg.value);
        WolkCreated(_participant, tokens); 
    }