Symbolize the Following Argument, and Test It for Validity

Symbolize the following argument, and test it for validity. If valid, construct a deduction;
if invalid, assign truth values that show that the premises can be while the conclusion is . Use these letters: D = The drought will continue.; S = We get an early storm.;
M = Managers of the ski areas will be happy.; F = There will be great fire danger next year.
Either there will be an early storm, or the drought will continue. If there's no continuation of the drought, then the managers of the ski areas will be happy and there will be no great danger of fire next year. So if we're to avoid any great danger of fire next year and to make the ski area managers happy, it will be necessary for there to be an early storm.