from sys import stderr
perr=lambda x:stderr.write(str(x)+"\n")
class INPUT:
  def __init__(self):
    self._l=open(0).read().split()
    self._length=len(self._l)
    self._index=0
    return

  def stream(self,k=1,f=int,f2=False):
    assert(-1<k)
    if self._length==self._index or self._length-self._index<k:
      raise Exception("There is no input!")
    elif f!=str:
      if k==0:
        ret=list(map(f,self._l[self._index:]))
        self._index=self._length
        return ret
      if k==1 and not f2:
        ret=f(self._l[self._index])
        self._index+=1
        return ret
      if k==1 and f2:
        ret=[f(self._l[self._index])]
        self._index+=1
        return ret
      ret=[]
      for _ in [0]*k:
        ret.append(f(self._l[self._index]))
        self._index+=1
      return ret
    else:
      if k==0:
        ret=list(self._l[self._index:])
        self._index=self._length
        return ret
      if k==1 and not f2:
        ret=self._l[self._index]
        self._index+=1
        return ret
      if k==1 and f2:
        ret=[self._l[self._index]]
        self._index+=1
        return ret
      ret=[]
      for _ in [0]*k:
        ret.append(self._l[self._index])
        self._index+=1
      return ret
pin=INPUT().stream

#pin(number[default:1],f[default:int],f2[default:False])
#if number==0 -> return left all
#listを変数で受け取るとき、必ずlistをTrueにすること。

class dsu:
  def __init__(self,n):
    assert n>0,"n must be Natural"
    self.n=n
    self.parents=[-1]*n
    return
  
  def find(self,x):
    assert x<self.n,"warning!! this is 0 index"
    if self.parents[x]<0:
      return x
    self.parents[x]=self.find(self.parents[x])
    return self.parents[x]
  
  def merge(self,x,y):
    assert x<self.n and y<self.n,"warning!! this is 0 index"
    x=self.find(x)
    y=self.find(y)
    if x==y:
      return
    if self.parents[x]>self.parents[y]:
      x,y=y,x
    self.parents[x]+=self.parents[y]
    self.parents[y]=x
    return
    
  def size(self,x):
    assert x<self.n,"warning!! this is 0 index"
    return -self.parents[self.find(x)]
    
  def same(self,x,y):
    assert x<self.n and y<self.n,"warning!! this is 0 index"
    return self.find(x)==self.find(y)
  
  def leader(self,x):
    assert x<self.n,"warning!! this is 0 index"
    if self.parents[x]<0:
      return x
    self.parents[x]=self.leader(self.parents[x])
    return self.parents[x]
  
  def groups(self):
    ld=[self.leader(i) for i in range(self.n)]
    res=[[] for _ in range(self.n)]
    for i in range(self.n):
      res[ld[i]].append(i)
    return list(filter(lambda a:a !=[],res))
    
def lcs(N,M,check):
  dp=[[0]*(M+1)for _ in[0]*(N+1)]
  for i in range(1,N+1):
    for j in range(1,M+1):
      if check[i-1][j-1]==1:
        dp[i][j]=dp[i-1][j-1]+1
      else:
        dp[i][j]=max(dp[i-1][j],dp[i][j-1])
  return dp[N][M]
  
def main():
  N,M,Q=pin(3)
  check=[[0]*M for _ in[0]*N]
  assert(1<=N<=1000)
  assert(1<=M<=1000)
  assert(1<=Q<=N*M)
  validation_set=set()
  for _ in[0]*Q:
    a,b=pin(2)
    assert(1<=a<=N)
    assert(1<=b<=M)
    validation_set.add((a,b))
    check[a-1][b-1]=1
  assert(len(validation_set)==Q)
  print(lcs(N,M,check))
  return

main()