#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

typedef priority_queue<int, vector<int>, greater<int>> pqmin;

const int MOD = 1e9+7;

int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }

int lcm(int a, int b) { return (a / gcd(a, b)) * b; }

int modpow(int a, int b, int mod = MOD) {

int res = 1;

while (b) {

if (b & 1) res = (res * a) % mod;

a = (a * a) % mod;

b >>= 1;

}

return res;

}

vector<int> sieve(int n) {

vector<int> isPrime(n + 1, 1);

isPrime[0] = isPrime[1] = 0;

for (int i = 2; i*i <= n; i++)

if (isPrime[i])

for (int j = i*i; j <= n; j += i)

isPrime[j] = 0;

return isPrime;

}

bool isPrime(int n) {

if (n <= 1) return false;

if (n <= 3) return true;

if (n % 2 == 0 || n % 3 == 0) return false;

for (int i = 5; i * i <= n; i += 6) {

if (n % i == 0 || n % (i + 2) == 0)

return false;

}

return true;

}

void solve(){

int n, m;

cin >> n >> m;

vector<pair<int,int>> v;

v.push_back({0,0});

for(int i=0;i<n;i++) {

int a,b;

cin>>a>>b;

v.push_back({a,b});

}

if (v.back().first < m)

v.push_back({m, 1 - v.back().second});

else

v.push_back({m, v.back().second});

int ans=0;

for(int i=0;i<(int)v.size()-1;i++){

int diff = v[i+1].first - v[i].first;

if(v[i+1].second != v[i].second){

if(diff % 2 == 0)

ans += diff - 1;

else

ans += diff;

}

else{

if(diff % 2 == 0)

ans += diff;

else

ans += diff - 1;

}

}

cout<<ans<<endl;

}

int main(){

ios::sync_with_stdio(0);

cin.tie(0);

int t = 1;

cin >> t;

while (t--) {

solve();

}

}