Complex sentence: The rifle divisions of the attacking armies had to receive additional men to continue to attack due to the high attrition rate in men, to maintain the offensive into September, for example, Konev requested 20,000 replacements for just two of the armies involved.
Split into simpler sentences: The rifle divisions of the attacking armies had to receive additional men to continue to attack due to the high attrition rate in men. To maintain the offensive into September, Konev requested 20,000 replacements for just two of the armies involved.