How many dragons are there in the legend of ice and fire?

Ice and Fire Legend has it that there are six dragons. Dragon nests are divided into frost dragon nests, dragon nests and electric dragon nests. Dragon nests are formed in plains, forests and deserts. The nests of frost maggots are formed in snowfields, snow-covered coniferous forests and glaciers. The nest of the electric dragon was born in the prairie. The nest of the tertiary dragon is formed on the ground of the above strata, and the nest of the tertiary dragon is formed underground of the above strata. The nest is densely packed with piles of precious metals, and there will be a certain number of trophy boxes containing trophies.