The rules for cross country skiing are similar to the ones created by International Ski Federation (FIS). They have been modified by the International Para Nordic Skiing Committee (IPNNC). Blind people and people with physical disabilities compete in cross country skiing. People with physical disabilities are separated into two groups. These are standing skiers and sitting skiers. People with physical disabilities who ski while standing are classified from LW2 to LW9. People with physical disabilities who use a sit ski are classified from LW10 to LW12. People who are blind are classified from B1 to B3. People who are blind use a guide skier. Guide skiers tell a blind skier which direction to ski.