số tự nhiên nhỏ nhất là 0
=> a=0
đáp số a=0
Là 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000nhé !