class segment_tree: __slots__ = ["op_M", "e_M","N","N0","dat"] def __init__(self, N, operator_M, e_M): self.op_M = operator_M self.e_M = e_M self.N = N self.N0 = 1<<(N-1).bit_length() self.dat = [self.e_M]*(2*self.N0) # 長さNの配列 initial で初期化 def build(self, initial): assert self.N == len(initial) self.dat[self.N0:self.N0+len(initial)] = initial[:] for k in range(self.N0-1,0,-1): self.dat[k] = self.op_M(self.dat[2*k], self.dat[2*k+1]) # a_k の値を x に更新 def update(self,k,x): k += self.N0 self.dat[k] = x k >>= 1 while k: self.dat[k] = self.op_M(self.dat[2*k], self.dat[2*k+1]) k >>= 1 # 区間[L,R]をopでまとめる def query(self,L,R): L += self.N0; R += self.N0 + 1 sl = sr = self.e_M while L < R: if R & 1: R -= 1 sr = self.op_M(self.dat[R],sr) if L & 1: sl = self.op_M(sl,self.dat[L]) L += 1 L >>= 1; R >>= 1 return self.op_M(sl,sr) def get(self, k): #k番目の値を取得。query[k,k]と同じ return self.dat[k+self.N0] n,m = map(int,input().split()) ab = [] for _ in range(n): a,b = sorted(map(int,input().split())) ab.append((a,b)) ab.sort() ans = 0 from operator import add seg = segment_tree(m,add,0) for a,b in ab: x = seg.query(a,b) ans += x seg.update(b,1) print(ans)