func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     vector<pair<long long, short> > mass;     long n, k;     scanf( %li %li , &n, &k);     long long a, b;     for (long i = 0; i < n; i++) {       scanf( %I64d %I64d , &a, &b);       mass.push_back(make_pair(a, -1));       mass.push_back(make_pair(b, 1));     }     sort(mass.begin(), mass.end());     vector<pair<long long, long long> > ans(n);     long long x = 0, balance = 0;     for (long i = 0; i < n * 2; i++) {       if (mass[i].second == -1 && balance == k - 1) ans[x].first = mass[i].first;       if (balance == k && mass[i].second == 1) ans[x++].second = mass[i].first;       balance -= mass[i].second;     }     printf( %I64d  n , x);     for (long i = 0; i < x; i++)       printf( %I64d %I64d  n , ans[i].first, ans[i].second);   }   