#include <bits/stdc++.h>
using namespace std;
struct event{
int s;
int a,b;
int inda,indb;
};
struct break_point{
int a;
int ind;
};
int n,k;
vector<event> t;
event null_event;
vector<int> h[200005];
vector<break_point> g;
vector<break_point> gs;
break_point u;
int m;
map<int,int,less<int>> ass;
int p=0;
int lmin=1e9,rmax=-1;
bool kis(break_point x,break_point y) {
return((x.a<y.a)||((x.a==y.a)&&(x.ind<y.ind)));
}
struct classcomp{
bool operator() (const event x,const event y) const {
return((x.a<y.a)||((x.a==y.a)&&(x.s<y.s)));
}
};
int max_place(int l,int r) {
int cur_ind=ass[l];
if ((h[cur_ind].size()==0)||(g[h[cur_ind][0]].a>r)) {
return(0);
}
int db=1,depth=1;
while ((h[cur_ind].size()>depth)&&(g[h[cur_ind][depth]].a<=r)) {
db=db*2; depth++;
}
return(max_place(g[h[cur_ind][depth-1]].a,r)+db);
}
bool intersect(event x,event y) {
return(!((x.b<=y.a)||(x.a>=y.b)));
}
int ans;
int ans2;
set<event,classcomp> an;
set<event,classcomp>::iterator it;
int d,e;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> k;
null_event.s=0; null_event.a=0; null_event.b=0; null_event.inda=-1; null_event.indb=-1;
t.assign(n+1,null_event);
for (int i=1;i<=n;i++) {
cin >> t[i].a >> t[i].b;
lmin=min(lmin,t[i].a);
rmax=max(rmax,t[i].b);
t[i].s=i;
if (ass.find(t[i].a)==ass.end()) {
u.a=t[i].a; u.ind=p; g.push_back(u);
ass[t[i].a]=p; p++;
}
t[i].inda=ass[t[i].a];
if (ass.find(t[i].b)==ass.end()) {
u.a=t[i].b; u.ind=p; g.push_back(u);
ass[t[i].b]=p; p++;
}
t[i].indb=ass[t[i].b];
if (h[t[i].inda].size()==0) {
h[t[i].inda].push_back(t[i].indb);
} else if (g[h[t[i].inda][0]].a>t[i].b) {
h[t[i].inda][0]=t[i].indb;
}
}
gs=g;
m=g.size();
sort(gs.begin(),gs.end(),kis);
for (int i=m-2;i>=0;i--) {
if (h[gs[i+1].ind].size()>0) {
if (h[gs[i].ind].size()==0) {
h[gs[i].ind].push_back(h[gs[i+1].ind][0]);
} else if (g[h[gs[i+1].ind][0]].a<g[h[gs[i].ind][0]].a) {
h[gs[i].ind][0]=h[gs[i+1].ind][0];
}
}
}
for (int j=1;j<=100;j++) {
for (int i=0;i<m;i++) {
if (h[gs[i].ind].size()<j) {
break;
}
if (h[h[gs[i].ind][j-1]].size()<j) {
break;
}
h[gs[i].ind].push_back(h[h[gs[i].ind][j-1]][j-1]);
}
}
/*
for (int i=0;i<m;i++) {
cout << i << ": " << gs[i].a << " " << gs[i].ind << " jumps: ";
for (int j:h[gs[i].ind]) {
cout << g[j].a << " ";
}
cout << endl;
}
int d,e;
while (true) {
cin >> d >> e;
cout << max_place(d,e) << endl;
}
*/
ans=max_place(lmin,rmax);
if (ans<k) {
cout << -1 << endl;
return(0);
}
event z;
z.a=-1e9;
z.b=lmin;
z.s=-1;
an.insert(z);
z.a=rmax;
z.b=1e9+1;
z.s=-2;
an.insert(z);
//cout << lmin << " " << rmax << endl;
for (int i=1;i<=n;i++) {
ans2=ans;
it=an.lower_bound(t[i]);
//cout << i << " " << (*it).s << endl;
//cout << (it==an.end()) << endl;
if (intersect(*it,t[i])) {
continue;
}
e=(*it).a;
it--;
//cout << i << " " << (*it).s << endl;
if (intersect(*it,t[i])) {
continue;
}
d=(*it).b;
ans2-=max_place(d,e);
ans2+=1;
ans2+=max_place(d,t[i].a);
ans2+=max_place(t[i].b,e);
if (ans2>=k) {
an.insert(t[i]);
ans=ans2;
}
if (an.size()==2+k) {
break;
}
//cout << ans << " " << ans2 << endl;
}
vector<int> kiir;
for (event i:an) {
if (i.s>0) {
kiir.push_back(i.s);
}
}
sort(kiir.begin(),kiir.end());
for (int i:kiir) {
cout << i << endl;
}
return 0;
}
/*
5 4
1 3
2 5
8 9
6 8
10 15
*/
