/*****************************************************************
    Author:lbn187, a konjac TwT
    Date:2016-3-26
    Contest:Codeforces
    Algorithm:QAQ
    ^_^  Orz hzh, NOI gold members, IOI 2016 world champion
    ^=^  Orz hhw, you are our blue moon, with you will live
    ^~^  Orz mxh, you are our red sun, without you we'll die
    ^-^  Orz yizhou, I wish you a successful marriage
    ^w^  Orz xianyangyu, you can sleep all the time in the game
*****************************************************************/
#pragma comment(linker, "/STACK:102400000,102400000")
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<map>
#include<set>
#include<bitset>
#define sf scanf
#define pf printf
#define fo(i,n) for(int i=0;i<n;i++)
#define fr(i,n) for(int i=1;i<=n;i++)
#define dr(i,n) for(int i=n;i;i--)
#define do(i,n) for(int i=n-1;i>=0;i--)
#define rep(i,a,n) for(int i=a;i<=n;i++)
#define per(i,a,n) for(int i=n;i>=a;i--)
#define mjj(i,x) for(int i=fir[x];i;i=ne[i])
#define X first
#define Y second
#define Max(a,b) a=max(a,b)
#define Min(a,b) a=min(a,b)
#define mp make_pair
#define rlr son[son[root][1]][0] 
#define gi(a) sf("%d",&a);
#define gi2(a,b) sf("%d%d",&a,&b);
#define gi3(a,b,c) sf("%d%d%d",&a,&b,&c);
#define gl(a) sf("%I64d",&a);
#define gs(s) sf("%s",s);
#define pi(a) pf("%d\n",a);
#define pi2(a,b) pf("%d %d\n",a,b);
#define pl(a) pf("%I64d\n",a);
#define spr(x) (x*x)
#define pie acos(-1) 
#define CM(a,b) memcpy(a,b,sizeof(b))
#define CL(a) memset(a,0,sizeof(a))
#define N 252222
#define M 1000000007
#define inf 1e9
#define eps 1e-8
using namespace std;

typedef long long LL;typedef unsigned long long ULL;typedef double LF;typedef long double LD;
typedef pair<int,int>pii;typedef pair<int,LL>pil;typedef pair<LL,int>pli;typedef pair<LL,LL>pll;typedef pair<LF,LF>pff;
const int xx[]={1,-1,0,0},yy[]={0,0,1,-1};LL pow(LL a,LL b,LL p){LL sum=1;for(a%=p;b;a=a*a%p,b>>=1)if(b&1)sum=sum*a%p;return sum;}
char ch;void rd(int &x){for(ch=getchar();ch<'0';ch=getchar());for(x=0;ch>='0';ch=getchar())x=x*10+ch-'0';}
LL phi(LL n){LL i,re=n;for(i=2;i*i<=n;i++)if(n%i==0){re=re/i*(i-1);while(n%i==0)n/=i;}if(n>1)re=re/n*(n-1);return re%M;}
void exgcd(LL a,LL b,LL &x,LL &y){if(!b){x=1;y=0;return;}exgcd(b,a%b,y,x);y-=x*(a/b);}
LL gcd(LL a,LL b){return b==0?a:gcd(b,a%b);}

int Q,n,m,x,y,i,j,tot,cnt,S,T,a[N],F[N];bool v[550][550];char s[550];LL A,B,C,ans;
struct P{int x,y;}q[N];
int G(int x,int y){return x*m-m+y;}
int gf(int x){return F[x]==x?x:F[x]=gf(F[x]);}
void uni(int x,int y){F[gf(x)]=gf(y);}
int main(){
    int W;
    for(scanf("%d",&W);W--;){
        scanf("%d%d",&n,&m);CL(v);
        for(i=1;i<=n;i++){
            scanf("%s",s+1);
            for(j=1;j<=m;j++)if(s[j]=='1')v[i][j]=1;
        }
        for(i=1;i<=n*m+2;i++)F[i]=i;S=n*m+1;T=S+1;
        for(scanf("%d",&Q),i=1;i<=Q;i++)scanf("%d%d",&q[i].x,&q[i].y),q[i].x++,q[i].y++,v[q[i].x][q[i].y]=1;
        for(i=1;i<=n;i++)for(j=1;j<=m;j++)if(!v[i][j]){
            if(i>1&&!v[i-1][j])uni(G(i-1,j),G(i,j)); 
            if(j>1&&!v[i][j-1])uni(G(i,j-1),G(i,j));
        }
        for(i=1;i<=m;i++)if(!v[1][i])uni(G(1,i),S);
        for(i=1;i<=m;i++)if(!v[n][i])uni(G(n,i),T);
        if(gf(S)==gf(T)){puts("-1");continue;}
        for(i=Q;i;i--){
            x=q[i].x;y=q[i].y;v[x][y]=0;
            if(x>1&&!v[x-1][y])uni(G(x-1,y),G(x,y));
            if(y>1&&!v[x][y-1])uni(G(x,y-1),G(x,y));
            if(x<n&&!v[x+1][y])uni(G(x+1,y),G(x,y));
            if(y<m&&!v[x][y+1])uni(G(x,y+1),G(x,y));
            if(x==1)uni(G(x,y),S);
            if(x==n)uni(G(x,y),T);
            if(gf(S)==gf(T)){printf("%d\n",i);break;}
        }
        if(gf(S)!=gf(T))puts("0");
        //fr(i,n)gi(a[i]);
    }
}