#include<iostream>#include<cstdio>#include<cmath>#include<cstring>#include<cstdlib>#include<cctype>#include<iomanip>#include<string>#include<algorithm>#include<ctime>#include<stack>#include<queue>#include<vector>#define N 105using namespace std;int m,n,ans,d;int map[N][N],dir[4][2]={1,0,-1,0,0,1,0,-1};bool legal(int x,int y){if(x>=1&&x<=m&&y>=1&&y<=n) return true;return false;}void DFS(int x,int y){int i,sx,sy;map[x][y]=1;d++;for(i=0;i<4;i++){sx=x+dir[i][0];sy=y+dir[i][1];if(legal(sx,sy)&&(!map[sx][sy]))DFS(sx,sy);}if(d>ans) ans=d;}int main(){ int i,j,x,y,k; while(cin>>m>>n>>k){memset(map,1,sizeof(map));while(k--){ cin>>x>>y; map[x][y]=0;} ans=0;for(i=1;i<=m;i++){for(j=1;j<=n;j++){if(!map[i][j]){d=0; DFS(i,j);}}}cout<<ans<<endl;}return 0;}
