The overall menu of an ethnic group goes through a three-generation process. The early arrivals, especially if they are working men who expect to return to their homelands, often eat almost entirely “American food,” obtaining ethnic specialties only in packages from home and for special occasions. Attempts to cook for themselves produce traditional foreign foods with simple substitutions for ingredients that are not in American markets. Thus early Chinese immigrants substituted iceberg lettuce for bean sprouts. Ethiopian immigrants used buckwheat or a mixture of wheat and rye flour to make flatbread until they could obtain the African millet traditionally used (later grown in the Rocky Mountain states). This pattern was less pronounced for immigrant groups who arrived in families, such as Irish Americans, who quickly located potatoes, leeks, cabbage, and oatmeal but had to substitute corned beef for spiced beef and German American sausages for their own.