#include<bits/stdc++.h>

using namespace std;

using lint = int64_t;

int main(){
    cin.tie(0)->sync_with_stdio(false);
    int n, k;
    cin>>n>>k;
    using pii = pair<lint, lint>;
    vector<pii> law(n), orglaw;
    for(auto &inter : law)
        cin>>inter.first>>inter.second;
    orglaw = law;
    sort(law.begin(), law.end());
    priority_queue<lint, vector<lint>, greater<lint>> pq;
    
    tuple<lint, lint, lint> ans = {0,-1e9,1e9};
    
    for(const auto &[l, r] : law){
        
        pq.push(r);
        if(pq.size() > k) pq.pop();
        if(pq.size() == k){
            lint max_r = pq.top();
            ans = max(ans, {max_r-l, l, max_r});
        }
    }

    auto [val, l, r] = ans;
    cout<<val<<"\n";
    for(int i =0; i<n; i++)
        if(k && orglaw[i].first <= l && r <= orglaw[i].second){
            k--;
            cout<<i+1<<" ";
        }
    cout<<"\n";
    return 0;
}