Use the fact that all even numbers have unique char. Then count the remaining numbers by subtracting the already counted ones.

```
def originalDigits(self, s):
count = [ 0 for _ in range(10)]
for c in s:
# numbers with unique char
if c == 'z':
count[0] += 1
if c == 'w':
count[2] += 1
if c == 'x':
count[6] += 1
if c == 'g':
count[8] += 1
if c == 'u':
count[4] += 1
# numbers derived from others:
if c == 'f':
count[5] += 1
if c == 'h':
count[3] += 1
if c == 's':
count[7] += 1
if c == 'o':
count[1] += 1
if c == 'i':
count[9] += 1
count[5] -= count[4]
count[3] -= count[8]
count[7] -= count[6]
count[1] -= (count[0] + count[2] + count[4])
count[9] -= (count[5] + count[6] + count[8])
result = []
for i in range(10):
for j in range(count[i]):
result.append(i)
return ''.join(str(num) for num in result)
```

'''