import sys # sys.setrecursionlimit(200005) int1 = lambda x: int(x)-1 pDB = lambda *x: print(*x, end="\n", file=sys.stderr) p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr) def II(): return int(sys.stdin.readline()) def LI(): return list(map(int, sys.stdin.readline().split())) def LLI(rows_number): return [LI() for _ in range(rows_number)] def LI1(): return list(map(int1, sys.stdin.readline().split())) def LLI1(rows_number): return [LI1() for _ in range(rows_number)] def SI(): return sys.stdin.readline().rstrip() # dij = [(0, 1), (-1, 0), (0, -1), (1, 0)] # dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)] # inf = (1 << 63)-1 inf = (1 << 31)-1 # md = 10**9+7 md = 998244353 from math import * # init_x, init_yは始線 class Vector: def __init__(self, x, y, init_x=1, init_y=0): self.x = x self.y = y self.norm2 = x*x+y*y self.norm = self.norm2**0.5 self.zone = 2 if x == y == 0: self.zone = -1 elif init_x*y-init_y*x > 0: self.zone = 1 elif init_x*y-init_y*x < 0: self.zone = 3 elif init_x*x+init_y*y > 0: self.zone = 0 def __repr__(self): return "({},{})".format(self.x, self.y) def __eq__(self, other): if self.zone != other.zone: return False return self.outer(other) == 0 def __lt__(self, other): if self.zone == other.zone: return self.outer(other) > 0 return self.zone < other.zone def __add__(self, other): return Vector(self.x+other.x, self.y+other.y) def __sub__(self, other): return Vector(self.x-other.x, self.y-other.y) def __iadd__(self, other): self.x += other.x self.y += other.y return self def __isub__(self, other): self.x -= other.x self.y -= other.y return self def __neg__(self): return Vector(-self.x, -self.y) def __mul__(self, val): return Vector(val*self.x, val*self.y) __rmul__ = __mul__ def __truediv__(self, val): assert val != 0 return Vector(self.x/val, self.y/val) def dot(self, v): return self.x*v.x+self.y*v.y def outer(self, v): return self.x*v.y-self.y*v.x def rot90(self): return Vector(-self.y, self.x) # Circle(r,Vector) or Circle(r,x,y) class Circle: def __init__(self, r, vx, oy=None): if not isinstance(vx, Vector): vx = Vector(vx, oy) self.o, self.r = vx, r def common_part(c1, c2): if c1.r < c2.r: c1, c2 = c2, c1 r1, o1 = c1.r, c1.o r2, o2 = c2.r, c2.o d = (o2-o1).norm d2 = (o2-o1).norm2 if d >= r1+r2: return 0 if r1 >= r2+d: return r2*r2*pi rad1 = acos((r1**2+d2-r2**2)/2/r1/d) rad2 = acos((r2**2+d2-r1**2)/2/r2/d) return r1*r1*(rad1-sin(rad1*2)/2)+r2*r2*(rad2-sin(rad2*2)/2) def radius(ll): aa = [0]*(len(ll)-1) bb = [0]*(len(ll)-1) s = m = 0 for i, l in enumerate(ll[:-1]): s += l m = max(m, l) aa[i] = s bb[i] = max(0, 2*m-s) return aa, bb n = II() x = II() ll = [II() for _ in range(n+1)] aa, bb = radius(ll) pp, qq = radius(ll[::-1]) pp.reverse() qq.reverse() # pDB(aa) # pDB(bb) # pDB(pp) # pDB(qq) for a, b, p, q in zip(aa, bb, pp, qq): if a == b or p == q: print(0) continue l1 = Circle(a, 0, 0) l2 = Circle(b, 0, 0) r1 = Circle(p, x, 0) r2 = Circle(q, x, 0) ans = common_part(l1, r1)-common_part(l1, r2)-common_part(l2, r1)+common_part(l2, r2) print(ans)