 Complete the following phrase:  On the front between the Bulgarian 3rd Army Slivnica-Trn-Caribrod and Serbian 2nd Army Sofia-Pirot-Niš, the main fighting took place outside Pirot on 6 and 7 July. A commander of the Serbian 2nd Army, general Stepa Stepanović suggested on 8 July that Pirot was to be evacuated. However, when the Romanian advance threatened the Bulgarian 1st Army on the evening the same day, the Bulgarian command ordered for withdrawal. Due to the Serbian victory 