Joisino is working as a receptionist at a theater.  The theater has 100000 seats, numbered from 1 to 100000.  According to her memo, N groups of audiences have come so far, and the i-th group occupies the consecutive seats from Seat l_i to Seat r_i (inclusive).  How many people are sitting at the theater now?
N=int(input())
ans=0
for _ in range(N):
  l,r=map(int,input().split())
  ans+=(r-l+1)
N=int(input())
ans=0
for _ in range(N):
  l,r=map(int,input().split())
  ans+=(r-l+1)
print(ans)