#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
#define REP(i,n) for(int i=(0);i<(n);i++)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef long long ll;

template<class T> inline void read(T &x){
    int f=0;x=0;char ch=getchar();
    for(;!isdigit(ch);ch=getchar())f|=(ch=='-');
    for(;isdigit(ch);ch=getchar())x=x*10+ch-'0';
    if(f)x=-x;
}

const int N=55;
namespace G{
    int f[N][N],x[N],y[N],vis[N],n,tim;
    inline void init(int _n){
        n=_n,tim=1;
        memset(f,0,sizeof f);
        memset(vis,0,sizeof vis);
        memset(x,0,sizeof x);
        memset(y,0,sizeof y);
    }
    int dfs(int u){
        vis[u]=tim;
        rep(v,1,n)
            if(f[u][v]){
                if(!y[v]||vis[y[v]]!=tim&&dfs(y[v])){
                    y[v]=u,x[u]=v;
                    return 1;
                }
            }
        return 0;
    }
    inline int solve(){
        int res=0;
        per(i,n,1)
            if(dfs(i))
                tim++,res++;
        return res;
    }
}
char s[N],t[N];
int m,n;

void MAIN(){
    read(m),read(n);
    G::init(n);
    rep(i,1,n)rep(j,1,n)
        G::f[i][j]=1;
    rep(i,1,m){
        scanf("%s%s",s+1,t+1);
        rep(a,1,n)rep(b,1,n)
            if(s[a]!=t[b])
                G::f[a][b]=0;
    }
    if(G::solve()<n){
        puts("-1");
        return;
    }
    rep(i,1,n-1)
        printf("%d ",G::x[i]);
    printf("%d\n",G::x[n]);
}

int main(){
    int T;
    read(T);
    while(T--)
        MAIN();
    
    return 0;
}