#include<bits/stdc++.h>
#define ls(x) (x<<1)
#define rs(x) (x<<1|1)
using namespace std;
constexpr int M=1e5+5,inf=0x3f3f3f3f;
int n,m,l,r,lg,tmp,st[20][M],tr[M<<2];
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 build(int l,int r,int x){
	tr[x]=0;if (l==r) return;int mid=l+r>>1;
	build(l,mid,ls(x));build(mid+1,r,rs(x));
}
void update(int p,int c,int l=1,int r=n,int x=1){
	if (l==r) return tr[x]=c,void();int mid=l+r>>1;
	p<=mid?update(p,c,l,mid,ls(x)):update(p,c,mid+1,r,rs(x));tr[x]=min(tr[ls(x)],tr[rs(x)]);
}
int query(int p,int l=1,int r=n,int x=1){
	if (l==r) return l; int mid=l+r>>1;
	return tr[ls(x)]<=p?query(p,l,mid,ls(x)):query(p,mid+1,r,rs(x));
}
void solve(){
	n=read();m=read();
	lg=31^__builtin_clz(n);
	for (int j=1;j<=lg;j++)
		for (int i=1;i+(1<<j)-1<=n;i++)
			st[j][i]=inf;
	auto upd=[&](auto l,auto r,auto p){
		int k=31^__builtin_clz(r-l+1);
		st[k][l]=min(st[k][l],p);
		st[k][r+1-(1<<k)]=min(st[k][r+1-(1<<k)],p);
	};
	for (int i=1;i<=n;i++) st[0][i]=i;
	for (int i=1;i<=m;i++) l=read(),r=read(),upd(l,r,l-1);
	for (int j=lg;j;j--)
		for (int i=1;i+(1<<j)-1<=n;i++)
			st[j-1][i]=min(st[j-1][i],st[j][i]),
			st[j-1][i+(1<<j-1)]=min(st[j-1][i+(1<<j-1)],st[j][i]);
	build(1,n,1);
	for (int i=1,tmp;i<=n;i++)
		printf("%d%c",tmp=query(st[0][i])," \n"[i==n]),update(tmp,i);
}
int main(){int T=read(); while (T--) solve(); return 0;}