Language: C++

#include"bits/stdc++.h"
using namespace std;
namespace ORIGIN {
#define LL long long
#define VLL vector<long long>
#define SORT(x) sort(x.begin(),x.end())
#define REVE(x) reverse(x.begin(),x.end())
#define rep(i,n) for(int i=0;i<n;i++)
#define COUT(x) cout<<x<<endl
#define WHOLE(x) x.begin(),x.end()
	double pai = 3.1415926535;
	string atc = "atcoder";
	typedef pair<long long, long long> data_t;
	string strnum = "0123456789";
	string alpS = "abcdefghijklmnopqrstuvwxyz";
	string alpL = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	int sizealp = (int)(alpS.size());
	int mod = 1e9 + 7;
	bool test = false;
}
using namespace ORIGIN;

void Test(char a) {
	if (test) {
		printf("%c", a);
	}
}
int gcd(LL a, LL b) {
	if (a == 0 || b == 0)return 0;
	if (a < b)swap(a, b);
	if (a % b == 0)return b;
	else gcd(b, a % b);
}
vector<int> nsinsuu(int base,int keta) {

}

int main() {
	int n, m;
	cin >> n >> m;
	VLL l, r;
	rep(i, m)cin >> l[i] >> r[i];
	COUT(max(0, min_element(WHOLE(r)) - max_element(WHOLE(l)) + 1));
}

Compiler output:
a.cc: In function 'std::vector<int> nsinsuu(int, int)':
a.cc:36:1: warning: no return statement in function returning non-void [-Wreturn-type]
   36 | }
      | ^
a.cc: In function 'int main()':
a.cc:43:17: error: no matching function for call to 'max(int, __gnu_cxx::__normal_iterator<long long int*, std::vector<long long int> >::difference_type)'
   43 |         COUT(max(0, min_element(WHOLE(r)) - max_element(WHOLE(l)) + 1));
      |              ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:9:23: note: in definition of macro 'COUT'
    9 | #define COUT(x) cout<<x<<endl
      |                       ^
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:43:17: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__normal_iterator<long long int*, std::vector<long long int> >::difference_type' {aka 'long int'})
   43 |         COUT(max(0, min_element(WHOLE(r)) - max_element(WHOLE(l)) + 1));
      |              ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:9:23: note: in definition of macro 'COUT'
    9 | #define COUT(x) cout<<x<<endl
      |                       ^
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:43:17: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   43 |         COUT(max(0, min_element(WHOLE(r)) - max_element(WHOLE(l)) + 1));
      |              ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:9:23: note: in definition of macro 'COUT'
    9 | #define COUT(x) cout<<x<<endl
      |                       ^
a.cc: In function 'int gcd(long long int, long long int)':
a.cc:32:17: warning: control reaches end of non-void function [-Wreturn-type]
   32 |         else gcd(b, a % b);
      |              ~~~^~~~~~~~~~