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

const int MAX=3e5+7;
int opening[MAX],closing[MAX];
int n,k;
vector<pair<int,int> >v;
vector<pair<int,pair<int,int> > >I;
multiset<int>open,close;

void f()
{
	int L=0,R=-1,c=0;
	int ans=0,op=0;
	for(auto j:v)
	{
		c++;
		I.push_back(make_pair(j.first,make_pair(0,c)));
		I.push_back(make_pair(j.second,make_pair(1,c)));
	}
	sort(I.begin(),I.end());
	for(auto j:I)
	{
		int c=j.second.second;
		if(j.second.first==0)
		{
			op++;
			open.insert(j.first);
			close.insert(closing[c]);
		}
		if(op>=k)
		{
			int r=*close.begin();
			int l=*open.rbegin();
			if(ans<r-l+1)
			{
				ans=r-l+1;
				L=l;
				R=r;
			}
		}
		if(j.second.first==1)
		{
			op--;
			auto k=open.find(opening[c]);
			open.erase(k);
			k=close.find(j.first);
			close.erase(k);
		}
	}
	if(ans==0)
	{
		cout<<0<<endl;
		for(int i=1;i<=k;i++)
			cout<<i<<" ";
		cout<<endl;
	}
	else
	{
		cout<<ans<<endl;
		c=0;
		for(auto j:v)
		{
			c++;
			if(k<=0)
				break;
			if(L>=j.first&&R<=j.second)
			{
				cout<<c<<" ";
				k--;
			}
		}
		cout<<endl;
	}
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin>>n>>k;
	for(int i=1;i<=n;i++)
	{
		int l,r;
		cin>>l>>r;
		v.push_back(make_pair(l,r));
		opening[i]=l;
		closing[i]=r;
	}
	f();
	return 0;
}