Is the Maghrib prayer valid if the worshiper intended four rak'ahs, then remembered that it is three rak'ahs?

If the worshiper thinks he will pray four rak'ahs in Maghrib prayer, then remembers it is three rak'ahs, his prayer is valid. The prayer is also valid, according to some scholars, if the worshiper intends at the 'takbirat al-ihram (definition)' to pray four rak'ahs for Maghrib, based on the condition that specifying the number of rak'ahs is not required. Therefore, an error in specifying the number does not harm, because specification is not a condition, and this is the view of the Maliki school.