LeetCode263:Ugly Number

 public bool IsUgly(int num) {
        if(num<1) return false;
			while(num>1)
			{
				if(num%2==0)
				{
					num=num/2;
				}
				else if(num%3==0)
				{
					num=num/3;
				}
				else if(num%5==0)
				{
					num=num/5;
				}
				else
				{
					return false;
				}
			}
			return true;
    }