function getTokensWithoutRestrictions(uint256 _usdAmount) public view returns (
        uint256 tokens,
        uint256 tokensExcludingBonus,
        uint256 bonus
    ) {
        if (_usdAmount == 0) {
            return (0, 0, 0);
        }

        uint256 tierIndex = getActualTierIndex();

        tokensExcludingBonus = _usdAmount.mul(1e18).div(getTokensInUSD(tierIndex));
        bonus = calculateBonusAmount(tierIndex, tokensExcludingBonus);
        tokens = tokensExcludingBonus.add(bonus);
    }