Ancestors Property share between two wifes children as w1(died) has one child and w2(alive) has four children

My father has married my mother and she died after one year of my birth and my father married another women and she has four children including three daughters whose got married in the past he(my father) has the property of 50 acres how it will be divided between us and how much share i will get. please give me exact share like 10 or 20 acres. I own 40 acres of land which i got from my mother father who purchased it from my village and transferred it to me .In that 40 acres of land my fathers brother took 20 acres of land forcefully when i was 25 years old as gift deed registration as i thought he also eligible to that property as there is no one to guide me at that point of time. Can i take it back or not as it is been 30 years since the land has transferred and he is demanding me more five acres of land now so i want to take it back is there any legal way to get it back. Does my father second wife children can claim my own property which i got through my mother father or not.Hindu Please clarify my doubts. Thank you.