class ST:
  def __init__(self,n):
    self.B=int(n**0.5)+1
    self.st1=[0]*self.B*self.B
    self.st2=[0]*self.B
    return
  
  def add(self,p,x):
    y=p//self.B
    self.st1[p]+=x
    self.st2[y]+=x
    return
  
  def sum(self,l,r):
    yl=l//self.B
    yr=r//self.B
    a=0
    if yl==yr:
      for i in range(l,r+1):
        a+=self.st1[i]
    else:
      for i in range(l,yl*self.B+self.B):
        a+=self.st1[i]
      for i in range(yl+1,yr):
        a+=self.st2[i]
      for i in range(yr*self.B,r+1):
        a+=self.st1[i]
    return a


n=int(input())
a=list(map(int,input().split()))
q=[]
z=[]
for i in range(n):
  l,r=map(int,input().split())
  q+=[(a[i]-l,0,a[i])]
  q+=[(a[i],1,a[i]+r)]
  z+=[a[i],a[i]+r]
z=sorted(set(z))
d={v:i for i,v in enumerate(z)}
st=ST(len(z))
a=0
q.sort()
for p,f,v in q:
  if f:
    a+=st.sum(d[p],d[v])
  else:
    st.add(d[v],1)
print(a-n)