#include<bits/stdc++.h>
using namespace std;
constexpr int M=2e5+5;
int n,m,num,cur,ans[M];
struct info{ int l,r;
    bool operator <(const info &a) const
        {return r==a.r?l<a.l:r<a.r;}
}a[M];
int read(){
    int x=0;char ch=getchar();
    while (!isdigit(ch)) ch=getchar();
    while (isdigit(ch)) x=x*10+ch-48,ch=getchar();
    return x;
}
void solve(){
    n=read();m=read();num=0;
    for (int i=1;i<=m<<1;i++){
        int l=read(),r=read();
        if (l<r) a[++num]={l,r};
    }
    if (num<m) return puts("-1"),void();
    sort(a+1,a+num+1); int cur=a[num-m].r+1;
    for (int i=1;i<=cur;i++) ans[i]=i;
    if (a[num-m].r==a[num-m+1].r) ans[a[num-m+1].l]=cur;
    for (int i=a[num-m+1].r-1;i<=n;i++) ans[i]=cur;
    for (int i=1;i<=n;i++) printf("%d%c",ans[i]," \n"[i==n]);
}
int main(){int T=read();while (T--) solve();return 0;}