This circuit checks and measures the parity of two qubits using a third ancillary qubit.
```python
from qiskit import QuantumCircuit
# Create circuit with 3 qubits and 1 classical bit
qc = QuantumCircuit(3, 1)
# Prepare qubits 0 and 1 in superposition
qc.h([0, 1])
# Use qubit 2 as ancilla for parity measurement
qc.cx(0, 2)
qc.cx(1, 2)
# Measure the ancilla qubit to determine the parity of qubits 0 and 1
qc.measure(2, 0)
```'Failed to run program: \'409 Client Error: Conflict for url: https://api.quantum.ibm.com/runtime/jobs. {"errors":[{"message":"You have reached the limit of 3 pending jobs. Please wait for a job to complete or cancel one before submitting anything new.","code":3458,"solution":"Wait until some previous jobs were finished. You can cancel pending jobs to run new jobs.","more_info":"https://docs.quantum-computing.ibm.com/errors"}]}\''