def transform_data(data):
    transformed_data = {
        'id': data['id'],
        'conversations': []
    }
    
    for conversation in data['conversations']:
        if conversation['from'] == 'human':
            transformed_data['conversations'].append({'input': conversation['value']})
        elif conversation['from'] == 'gpt':
            transformed_data['conversations'][-1]['output'] = conversation['value']
            
    return transformed_data