How many days can the body survive without water?

In a harsh environment — it's snowing, say — you have 3 hours to survive without shelter. After 3 days, you need water or you'll perish. You can make it 3 weeks without food, though we promise you that won't be fun.

After 3 days, you need water or you'll perish. You can make it 3 weeks without food, though I promise you that won't be fun.

Is that a negative 22 or a positive?