A_Shape_Perimeter.cpp

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

typedef long long ll;
typedef pair<ll, ll> pll;
typedef vector<bool> vbl;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<string> vstr;
typedef vector<pll> vpll;

#define endl '\n'
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
constexpr ll mod = 1000000007;

inline void Parvez() { ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0); }
template<class T>inline istream& operator>>(istream& in, vector<T>& v) { for (T& x : v) { in >> x; }return in; }template<class T>inline ostream& operator<<(ostream& out, vector<T>& v) { for (ll i = 0;i < v.size() - 1;i++) { out << v[i] << ' '; }out << v[v.size() - 1];return out; }
inline void inp() {}template<class H, class... T>inline void inp(H&& h, T &&...t) { cin >> h;inp(forward<T>(t)...); }inline void print() { cout << endl; }template<class H, class... T>inline void print(H&& h, T &&...t) { cout << h;if (sizeof...(t) != 0)cout << ' ';print(forward<T>(t)...); }


bool cmp(pll a, pll b) {
	return a.first < b.first or (a.first == b.first && a.second < b.second);
}

void solution(ll& T) {
	ll n, m; inp(n, m);
	vector<pair<ll, ll>> v(n);
	for (ll i = 0; i < n; i++) {
		cin >> v[i].first >> v[i].second;
	}
	// sort(all(v), cmp);
	// for (auto [i, j] : v) {
	// 	cout << i << ' ' << j << endl;
	// }
	// print();
	ll ans = 0;

	for (ll i = 0; i < n; i++) {
		if (i == 0) {
			ans += 4 * m;
			continue;
		}
		ans += 4 * m;

		if (v[i].first >= m and v[i].second >= m) continue;
		ans -= (m-v[i].first) * 2 + (m-v[i].second) * 2;
	}
	cout << ans << endl;
	// print();
}

signed main() {
	Parvez();
	ll TT = 1;
	cin >> TT;
	for (ll T = 1;T <= TT;T++)
		solution(T);
	return 0;
}