05. Project Prize

# 05. Project Prize

parts_project = int(input())
money_parts = float(input())
points = 0
moment_points = 0

for i in range(parts_project):
    current_points = int(input())
    points += 1
    if points %2 == 0:
        moment_points += current_points * 2
    else:
        moment_points += current_points
end_prize = moment_points * money_parts
print(f"The project prize was {end_prize:.2f} lv.")