state = '##.##.##.##....##.##.##.##.##.##.##.##.##....##.##.##.##.##.##.##.##.##....##.##.##....##.##.##.##.##.##....##.##.##.##.##.##.##.##....##.##.##.##.##.##.##.##.##.##'

gens = 50000000000

start_idx = gens - 64

res = 0
for i, pot_val in enumerate(state):
    pot_id = i + start_idx
    if pot_val == '#':
        res += pot_id
print(res)