from sys import stdin, stdout
input=stdin.readline

def s():
 N,K,M=map(int,input().split())
 szobak=tuple(map(int,input().split()))
 lepesek=[tuple(map(int,input().split())) for i in range(M)]

 def test(start):
  for a,b in lepesek:
   if szobak[start]==a:
    start+=b
    if start==N:
     return 1
    elif start==-1:
     return -1
  return 0

 res=0
 first=test(0)
 last=test(N-1)
 if last==1:
  if first==1:return N 
  else:
   lo=0
   hi=N-1
   while hi-lo>1:
    mid=(hi+lo)//2
    if test(mid)==1:hi=mid
    else:lo=mid
   res+=N-hi
 if first==-1:
  if last==-1:return N
  else:
   lo=0
   hi=N-1
   while hi-lo>1:
    mid=(hi+lo)//2
    if test(mid)==-1:lo=mid
    else:hi=mid
   res+=hi
 return res

stdout.write(str(s())+'\n')