One hundred Samvatsaras is the maximum age of men.
Satya, Treta, Dvapara and Kali a cycle of these 4 Yugas and their
Sandhyas and Sandhyansas consist of 12 thousand divine years.
The beginning of a Yuga is its Sandhya. Tho end of a Yuga is its
Sandhyansa. Sandhya and Sandhyansa are not included in a Yuga and Yuga
Dharma is not to be performed while they last.
Sandhya of Satya Yuga = 400 Deva years.