#include<bits/stdc++.h>
using namespace std;

namespace ModInt{
	template <uint32_t mod>
	struct mint
	{
		#define i32 int32_t
		#define u32 uint32_t
		#define u64 uint64_t
		static constexpr u32 get_r(){u32 ret=mod;for(i32 i=0;i<4;++i)ret*=2-mod*ret;return ret;}
		static constexpr u32 r=get_r();
		static const u32 n2=-u64(mod)%mod;
		static const u32 mod2=mod<<1;
		u32 a;
		constexpr mint():a(0){}
		constexpr mint(const int64_t &b):a(reduce(u64(b%mod+mod)*n2)){};
		static constexpr u32 reduce(const u64 &b){return (b+u64(u32(b)*u32(-r))*mod)>>32;}
		const mint &operator+=(const mint &b){if(i32(a+=b.a-mod2)<0)a+=mod2;return *this;}
		const mint &operator-=(const mint &b){if(i32(a-=b.a)<0)a+=mod2;return *this;}
		const mint &operator*=(const mint &b){a=reduce(u64(a)*b.a);return *this;}
		const mint &operator/=(const mint &b){*this*=b.inverse();return *this;}
		const mint operator+(const mint &b)const{return mint(*this)+=b;}
		const mint operator-(const mint &b)const{return mint(*this)-=b;}
		const mint operator*(const mint &b)const{return mint(*this)*=b;}
		const mint operator/(const mint &b)const{return mint(*this)/=b;}
		const bool operator==(const mint &b)const{return(a>=mod?a-mod:a)==(b.a>=mod?b.a-mod:b.a);}
		const bool operator!=(const mint &b)const{return(a>=mod?a-mod:a)!=(b.a>=mod?b.a-mod:b.a);}
		const mint operator-()const{return mint()-mint(*this);}
		const mint ksm(u64 n)const{mint ret(1);for(mint mul(*this);n;n>>=1,mul*=mul)if(n&1)ret*=mul;return ret;}
		const mint inverse()const{return ksm(mod-2);}
		friend ostream &operator<<(ostream &os, const mint &b){return os<<b.get();}
		friend istream &operator>>(istream &is, mint &b){int64_t t;is>>t;b=mint(t);return(is);}
		const u32 get()const{u32 ret=reduce(a);return ret>=mod?ret-mod:ret;}
		static const u32 get_mod(){return mod;}
	};
}
using namespace ModInt;

namespace FAST_IO{
	#define ll long long
	#define ull unsigned long long
	#define db double
	#define _8 __int128_t
	#define Get() (BUF[Pin++])
	const int LEN=1<<20;
	char BUF[LEN];
	int Pin=LEN;
	inline void flushin(){memcpy(BUF,BUF+Pin,LEN-Pin),fread(BUF+LEN-Pin,1,Pin,stdin),Pin=0;return;}
	inline char Getc(){return (Pin==LEN?(fread(BUF,1,LEN,stdin),Pin=0):0),BUF[Pin++];}
	template<typename tp>inline tp read(){(Pin+40>=LEN)?flushin():void();tp res=0;char f=1,ch=' ';for(;ch<'0'||ch>'9';ch=Get())if(ch=='-')f=-1;for(;ch>='0'&&ch<='9';ch=Get())res=(res<<3)+(res<<1)+ch-48;return res*f;}
	template<typename tp>inline void read(tp &n){(Pin+40>=LEN)?flushin():void();tp res=0;char f=1,ch=' ';for(;ch<'0'||ch>'9';ch=Get())if(ch=='-')f=-1;for(;ch>='0'&&ch<='9';ch=Get())res=(res<<3)+(res<<1)+ch-48;n=res*f;return;}
	inline int readstr(char *s){int len=0;char ch=Getc();while(!isalnum(ch))ch=Getc();while(isalnum(ch))s[len++]=ch,ch=Getc();return len;}
	#define Put(x) (PUF[Pout++]=x)
	char PUF[LEN];
	int Pout;
	inline void flushout(){fwrite(PUF,1,Pout,stdout),Pout=0;return;}
	inline void Putc(char x){if(Pout==LEN)flushout(),Pout=0;PUF[Pout++]=x;}
	template<typename tp>inline void write(tp a,char b='\n'){static int stk[40],top;(Pout+50>=LEN)?flushout():void();if(a<0)Put('-'),a=-a;else if(a==0)Put('0');for(top=0;a;a/=10)stk[++top]=a%10;for(;top;--top)Put(stk[top]^48);Put(b);return;}
	inline void wt_str(string s){for(char i:s)Putc(i);return;}
}
using namespace FAST_IO;

#define pii pair<int,int>
#define fi first
#define se second
#define ls (rt<<1)
#define rs (rt<<1|1)
#define Ls (tr[rt].lc)
#define Rs (tr[rt].rc)

const int N=2e5+10;
int T,n,m,ans[N],tot;
struct Seg{
	int l,r;
}a[N];
bool cmp(Seg a,Seg b)
{
	return a.r==b.r?a.l>b.l:a.r<b.r;
}
int main()
{
	read(T);
	while(T--)
	{
		read(n),read(m);
		tot=0;
		for(int i=1,l,r;i<=2*m;i++)
		{
			read(l),read(r);
			if(l!=r)a[++tot]={l,r};		
		}
		if(tot<m)
		{
			write(-1);
			continue;
		}
		sort(a+1,a+tot+1,cmp);
		for(int i=1;i<=a[tot-m].r;i++)ans[i]=i;
		int v=a[tot-m].r;
		if(a[tot-m].r==a[tot-m+1].r)ans[a[tot-m+1].l]=v;
		for(int i=a[tot-m].r+1;i<=n;i++)ans[i]=v;
		for(int i=1;i<=n;i++)
			write(ans[i],i<n?' ':'\n');
	}
	flushout();
	return 0;
}