Wheat is the staple food for most Afghans, comprising more than 70 percent of their diet. Low-quality rice is a poor, but sometimes necessary, substitute. All markets represent significant population centers and consumer markets. Kabul, the capital, supplies the central provinces and is a transit point between the north, south, east, and west. Jalalabad supplies the eastern part of the country and acts as a cross-border market with Pakistan. Mazar-e-Sarif supplies northern provinces and, in a good year, the southern provinces as well.