#include<bits/stdc++.h> 
#define For(i,j,k) for (int i=(int)(j);i<=(int)(k);i++)
#define Rep(i,j,k) for (int i=(int)(j);i>=(int)(k);i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define ll long long
#define fi first
#define se second
#define PB push_back
#define uint unsigned
#define ull unsigned ll 
using namespace std;
pll hsh1[55],hsh2[55];
int n,m,ans[55];
char s[55];
void solve(){
    scanf("%d%d",&n,&m);
    For(i,1,m) hsh1[i]=hsh2[i]=pll(0,i);
    For(i,1,n){
        scanf("%s",s+1);
        For(j,1,m) hsh1[j].fi=hsh1[j].fi*233+s[j];
        scanf("%s",s+1);
        For(j,1,m) hsh2[j].fi=hsh2[j].fi*233+s[j];
    }
    sort(hsh1+1,hsh1+m+1);
    sort(hsh2+1,hsh2+m+1);
    For(i,1,m)
        if (hsh1[i].fi!=hsh2[i].fi)
            return puts("-1"),void(0);
    For(i,1,m)
        ans[hsh1[i].se]=hsh2[i].se;
    For(i,1,m) printf("%d%c",ans[i],i==m?'\n':' ');
}
int main(){
    int T;
    scanf("%d",&T);
    while (T--) solve(); 
}