Task: Question Answering
Input (English): Passage: Crimean Khan Haji Giray, learning of the defeat of the Budjak Tatars gathered 10,000-12,000 men and went against Kunitsky. At the end of December Kunitsky with 10,000-12,000 Cossacks and Moldavians left Budjak and began to cross the Prut River near the village of Tobak, not far from the town of Reni, Ukraine. Here on 30 December they were suddenly attacked by Tatar cavalry under Khan Haji Giray. Kunitsky built a fortified camp and successfully repelled the Tatar attacks. On the night of 3 to 4 January 1684 the Moldavian allies betrayed the Cossacks and left the Cossack camp. In this situation Kunitsky with the Cossack cavalry  broke through the enemy ring and crossed the Prut. The Cossack infantry  under Andrey Mogila also broke out and crossed the Prut near Boyanova, but suffered heavy losses. By 10 January only five thousand Cossacks reached Jassy. 
Question: How many days after the Cossacks and Moldavians were attacked by Tatar calalry under Khan Haji Giray did the Moldavian allies betray the Cossacks? 
Answer type: Number 
Output (English): 4.