rt，寄录

#include<bits/stdc++.h>
using namespace std;
typedef int ll;
const int maxn=3005;
const ll INF=114514191;
ll n,m,k,a[maxn][maxn],fp1,fp2=1,mins=INF,mine=INF;
ll vis[maxn][maxn],vis2[maxn][maxn],xv[5]={1,0,-1,0},yv[5]={0,-1,0,1};
bool buc[maxn][maxn],buc2[maxn*maxn];
void bfs(void){
	queue<pair<ll,ll> > q;
	q.push(make_pair(1,1));
	vis[1][1]=0;
	pair<ll,ll> u,v;
	while(!q.empty()){
		u=q.front(),q.pop();
		if(buc[u.first][u.second]==1&&mins>=vis[u.first][u.second]){
			if(fp1) buc2[a[u.first][u.second]]=1;
			else mins=vis[u.first][u.second];
		}
		for(int i=0;i<=3;i++){
			v.first=u.first+xv[i],v.second=u.second+yv[i];
			if(vis[v.first][v.second]==INF&&a[v.first][v.second]){
				vis[v.first][v.second]=vis[u.first][u.second]+1;
				q.push(v);
			}
		}
	}
}
void bfs2(void){
	queue<pair<ll,ll> > q;
	q.push(make_pair(n,m));
	vis2[n][m]=0;
	pair<ll,ll> u,v;
	while(!q.empty()){
		u=q.front(),q.pop();
		if(buc[u.first][u.second]==1&&mine>=vis2[u.first][u.second]){
			if(buc2[a[u.first][u.second]]==1) fp2=0;
			mine=vis2[u.first][u.second];
		}
		for(int i=0;i<=3;i++){
			v.first=u.first+xv[i],v.second=u.second+yv[i];
			if(vis2[v.first][v.second]==INF&&a[v.first][v.second]){
				vis2[v.first][v.second]=vis2[u.first][u.second]+1;
				q.push(v);
			}
		}
	}
}
int main(void){
	//freopen("dream5.in","r",stdin);
	ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	cin>>n>>m>>k;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m;j++){
			cin>>a[i][j];
			vis[i][j]=vis2[i][j]=INF;
		}
	}
	ll px,py;
	for(int i=1;i<=k;i++){
		cin>>px>>py;
		buc[px][py]=1;
	}
	bfs();
	fp1=1;
	if(k<=1){
		if(vis[n][m]==INF||a[1][1]==0) cout<<-1;
		else cout<<vis[n][m];
		return 0;
	}
	bfs();
	bfs2();
	if(mins==INF||mine==INF){
		cout<<-1;
		return 0;
	}
	//cout<<mins<<" "<<mine<<" "<<fp2<<endl;
	cout<<min(vis[n][m],mins+mine+fp2+1);
	return 0;
}