#include <cstdio>

#include <cstring>

#include <algorithm>

#define pos(a,b) (((a)-1)*m+(b))

typedef long long LL;

const int N=;

const int P=N*N;

const int E=P*;

const LL Inf=0x3f3f3f3f3f3f3f3fLL;

struct V{

  int to,next;

  LL f;

}c[E];

int head[P],t;

inline void add(int x,int y,LL z){

  c[++t].to=y,c[t].next=head[x],head[x]=t,c[t].f=z;

}

inline void clear(){

  memset(head,,sizeof(head)),t=;

}

int n,m;

int S,T;

int deep[P],q[P],front,back;

inline bool bfs(){

  memset(deep,,sizeof(deep));

  front=back=,q[back++]=S,deep[S]=;

  while(front!=back){

    int x=q[front++];

    for(int i=head[x];i;i=c[i].next)

      if(c[i].f&&deep[c[i].to]==){

        deep[c[i].to]=deep[x]+;

        if(c[i].to==T)return true;

        q[back++]=c[i].to;

      }

  }return false;

}

inline LL dfs(int x,LL v){

  if(x==T||v==)return v;

  LL ret=;

  for(int i=head[x];i;i=c[i].next)

    if(c[i].f&&deep[c[i].to]==deep[x]+){

      LL f=dfs(c[i].to,std::min(c[i].f,v));

      ret+=f,v-=f,c[i].f-=f,c[i^].f+=f;

      if(v==)break;

    }

  if(ret==)deep[x]=;

  return ret;

}

int cnt[];

LL sum[];

int max,val[N][N];

inline LL dinic(){

  LL ret=;

  while(bfs())ret+=dfs(S,Inf);

  return ret;

}

inline bool check(LL ans){

  clear();LL ret=;

  for(int i=;i<=n;++i)

    for(int j=;j<=m;++j)

      if((i+j)&){

        if(i>)

          add(pos(i,j),pos(i-,j),Inf),add(pos(i-,j),pos(i,j),);

        if(j>)

          add(pos(i,j),pos(i,j-),Inf),add(pos(i,j-),pos(i,j),);

        if(i<n)

          add(pos(i,j),pos(i+,j),Inf),add(pos(i+,j),pos(i,j),);

        if(j<m)

          add(pos(i,j),pos(i,j+),Inf),add(pos(i,j+),pos(i,j),);

        add(S,pos(i,j),ans-val[i][j]),add(pos(i,j),S,);

        ret+=ans-val[i][j];

      }else

        add(pos(i,j),T,ans-val[i][j]),add(T,pos(i,j),);

  return ret==dinic();

}

inline void work1(){

  if((sum[]-sum[])%(cnt[]-cnt[])!=){

    puts("-1");return;

  }

  LL ans=(sum[]-sum[])/(cnt[]-cnt[]);

  if(check(ans))

    printf("%lld\n",(ans*n*m-(sum[]+sum[]))>>1LL);

  else puts("-1");

}

inline void work2(){

  if(sum[]!=sum[]){

    puts("-1");return;

  }

  LL l=max,r=Inf/5000LL,mid,ans=;

  while(l<=r){

    mid=(l+r)>>;

    if(check(mid))

      ans=mid,r=mid-;

    else

      l=mid+;

  }

  if(ans==)puts("-1");

  else printf("%lld\n",(ans*n*m-(sum[]+sum[]))>>1LL);

}

int main(){

  int test;scanf("%d",&test);

  while(test--){

    scanf("%d%d",&n,&m);

    memset(cnt,,sizeof(cnt));

    memset(sum,,sizeof(sum));

    max=,S=n*m+,T=n*m+;

    for(int i=;i<=n;++i)

      for(int j=;j<=m;++j){

        scanf("%d",&val[i][j]);

        ++cnt[(i+j)&],sum[(i+j)&]+=val[i][j];

        max=std::max(max,val[i][j]);

      }

    if(cnt[]!=cnt[])work1();

    else work2();

  }return ;

}