#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
#define rep(i,s,t) for(register int i=s;i<=t;++i)
#define _rep(i,s,t) for(register int i=s;i>=t;--i)
const int N=1e5+11;
char S[N],T[N];
int f[233][233];
int ss[233][233];
int tt,n,m,mt[233],mc[233],vis[233];
inline bool cmp(int x,int y){
    return x>y;
}
inline bool dfs(int x,int dep){
    rep(i,1,m)
        if(f[x][i]&&!mt[i]){
            mt[i]=x;
            mc[x]=i;
            return 1;
        }
    int top=0,p=0,o;
    rep(i,1,m)
        if(f[x][i]&&mt[i]&&!vis[i])
            ss[dep][++top]=mt[i];
    sort(ss[dep]+1,ss[dep]+top+1,cmp);
    rep(i,1,top){
        o=ss[dep][i];
        vis[mc[o]]=1;
        if(dfs(o,dep+1)){
            mc[x]=mc[o];
            mt[mc[o]]=x;
            return 1;
        }
    }
    return 0;
}
int main(){
    scanf("%d",&tt);
    while(tt--){
        scanf("%d%d",&n,&m);
        rep(i,1,m){
            rep(j,1,m)
                f[i][j]=1;
            mt[i]=0;
        }
        rep(i,1,n){
            scanf("%s%s",S+1,T+1);
            rep(j,1,m)
                rep(k,1,m)
                    if(S[j]!=T[k])
                        f[j][k]=0;
        }
        rep(i,1,m){
            memset(vis,0,sizeof vis);
            if(!dfs(i,0)){
                puts("-1");
                goto end;
            }
        }
        rep(i,1,m-1)
            printf("%d ",mc[i]);
        printf("%d\n",mc[m]);
        end:;
    }
    return 0;
}