#include <bits/stdc++.h>
using namespace std;
struct event {
int l, r;
bool operator < ( const event e ) const {
if ( l == e.l )
return r < e.r;
return l < e.l;
}
};
const int MAX_N = 1e5;
const int MAX_M = 2 * MAX_N;
int bucket[MAX_M + 2], leftBucket[MAX_M + 1], rightBucket[MAX_M + 1], maxEvents[MAX_M + 1], eventRightEnd[MAX_M + 1], minR[MAX_M + 2];
event events[MAX_N + 1];
set<int> rightEnds[MAX_M + 1];
set<event> selectedEvents;
map<int, int> normal;
bool check ( event e ) {
auto p = selectedEvents.lower_bound( e );
if ( e.r <= p->l && (--p)->r <= e.l )
return true;
return false;
}
void calcBucket( int b ) {
for ( int i = rightBucket[b]; i >= leftBucket[b]; i-- ) {
maxEvents[i] = 0;
eventRightEnd[i] = i;
if ( bucket[i + 1] == b ) {
if ( maxEvents[i + 1] > maxEvents[i] ) {
maxEvents[i] = maxEvents[i + 1];
eventRightEnd[i] = eventRightEnd[i + 1];
}
}
if ( !rightEnds[i].empty() && bucket[*rightEnds[i].begin()] == b ) {
if ( maxEvents[*rightEnds[i].begin()] + 1 > maxEvents[i] ) {
maxEvents[i] = maxEvents[*rightEnds[i].begin()] + 1;
eventRightEnd[i] = eventRightEnd[*rightEnds[i].begin()];
} else if ( maxEvents[*rightEnds[i].begin()] + 1 == maxEvents[i] )
eventRightEnd[i] = min( eventRightEnd[i], eventRightEnd[*rightEnds[i].begin()] );
}
}
}
int query( int l, int r ) {
int nrEvents = 0;
while ( eventRightEnd[l] <= r ) {
nrEvents += maxEvents[l];
l = eventRightEnd[l];
nrEvents++;
l = minR[l];
}
while ( l <= r ) {
nrEvents++;
l = minR[l];
}
return nrEvents - 1;
}
int main() {
int n, k;
cin >> n >> k;
for ( int i = 1; i <= n; i++ ) {
cin >> events[i].l >> events[i].r;
normal[events[i].l] = 1;
normal[events[i].r] = 1;
}
int m = 0;
for ( auto p: normal )
normal[p.first] = ++m;
for ( int i = 1; i <= n; i++ ) {
events[i].l = normal[events[i].l];
events[i].r = normal[events[i].r];
rightEnds[events[i].l].insert( events[i].r );
}
minR[m + 1] = m + 1;
for ( int i = m; i >= 1; i-- )
minR[i] = min( minR[i + 1], (!rightEnds[i].empty() ? *rightEnds[i].begin() : m + 1) );
int bucketSize = sqrt( m ), nrBuckets = 0;
for ( int i = 1; i <= m; i += bucketSize ) {
nrBuckets++;
leftBucket[nrBuckets] = i;
rightBucket[nrBuckets] = min( i + bucketSize - 1, m );
for ( int j = i; j < i + bucketSize && j <= m; j++ )
bucket[j] = nrBuckets;
calcBucket( nrBuckets );
}
eventRightEnd[m + 1] = m + 1;
selectedEvents.insert( { 1, 1 } );
selectedEvents.insert( { m, m } );
vector<int> ans;
int nrEvents = query( 1, m );
for ( int i = 1; i <= n && k > 0; i++ ) {
if ( !check( events[i] ) )
continue;
auto p = selectedEvents.lower_bound( events[i] );
int r = p->l;
p--;
int l = p->r;
int copyNrEvents = nrEvents;
nrEvents -= query( l, r );
rightEnds[events[i].l].erase( events[i].r );
calcBucket( bucket[events[i].l] );
nrEvents += query( l, events[i].l ) + query( events[i].r, r );
if ( nrEvents >= k - 1 ) {
selectedEvents.insert( events[i] );
ans.push_back( i );
k--;
} else
nrEvents = copyNrEvents;
}
if ( k > 0 ) {
cout << -1;
return 0;
}
for ( int i: ans )
cout << i << "\n";
return 0;
}
