def quantum_full_adder(
    input_1: int = 1, input_2: int = 1, carry_in: int = 1
) -> qiskit.result.counts.Counts:
    if (
        isinstance(input_1, str)
        or isinstance(input_2, str)
        or isinstance(carry_in, str)
    ):
        raise TypeError("inputs must be integers.")

    if (input_1 < 0) or (input_2 < 0) or (carry_in < 0):
        raise ValueError("inputs must be positive.")

    if (
        (math.floor(input_1) != input_1)
        or (math.floor(input_2) != input_2)
        or (math.floor(carry_in) != carry_in)
    ):
        raise ValueError("inputs must be exact integers.")

    if (input_1 > 2) or (input_2 > 2) or (carry_in > 2):
        raise ValueError("inputs must be less or equal to 2.")

    # build registers
    qr = qiskit.QuantumRegister(4, "qr")
    cr = qiskit.ClassicalRegister(2, "cr")
    # list the entries
    entry = [input_1, input_2, carry_in]

    quantum_circuit = qiskit.QuantumCircuit(qr, cr)

    for i in range(0, 3):
        if entry[i] == 2:
            quantum_circuit.h(i)  # for hadamard entries
        elif entry[i] == 1:
            quantum_circuit.x(i)  # for 1 entries
        elif entry[i] == 0:
            quantum_circuit.i(i)  # for 0 entries

    # build the circuit
    quantum_circuit.ccx(0, 1, 3)  # ccx = toffoli gate
    quantum_circuit.cx(0, 1)
    quantum_circuit.ccx(1, 2, 3)
    quantum_circuit.cx(1, 2)
    quantum_circuit.cx(0, 1)

    quantum_circuit.measure([2, 3], cr)  # measure the last two qbits

    backend = qiskit.Aer.get_backend("aer_simulator")
    job = qiskit.execute(quantum_circuit, backend, shots=1000)

    return job.result().get_counts(quantum_circuit)