`x` is a good number if after rotating each digit individually by 180 degrees, we get a valid number that is different from `x`. Each digit must be rotated - we cannot choose to leave it alone.

A number is valid if each digit remains a digit after rotation. 0, 1, and 8 rotate to themselves; 2 and 5 rotate to each other (on this case they are rotated in a different direction, in other words 2 or 5 gets mirrored); 6 and 9 rotate to each other, and the rest of the numbers do not rotate to any other number and become invalid.

Now given a positive number `n`, how many numbers `x` from `1` to `n` are good?

```Example:
Input: 10
Output: 4
Explanation:
There are four good numbers in the range [1, 10] : 2, 5, 6, 9. ```

Note that 1 and 10 are not good numbers, since they remain unchanged after rotating.

c++ implementation:

```    int rotatedDigits(int n)
{
int c=0;
while(n)
{
int x=n;
int f=0;
while(x)
{
int d=x%10;
if(d==3 ||d==4||d==7)
{
f=0;
break;
}
else if(d== 2 || d == 5 || d == 6 || d == 9)
{
f=1;
}
x=x/10;
}
if(f==1)
c++;

n=n-1;
}
return c;
}```

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