#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef pair<int, int> pii;
#ifdef DEBUG
#define display(x) cerr << #x << " = " << x << endl;
#define displaya(a, st, n)\
    {cerr << #a << " = {";\
    for(int qwq = (st); qwq <= (n); ++qwq) {\
        if(qwq == (st)) cerr << a[qwq];\
        else cerr << ", " << a[qwq];\
    } cerr << "}" << endl;}
#define displayv(v) displaya(v, 0, (int)(v).size() - 1)
#define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
#define display(x) ;
#define displaya(a, st, n) ;
#define displayv(v) ;
#define eprintf(...) if(0) fprintf(stderr, "...")
#endif
template<typename T> bool chmin(T &a, const T &b) { return a > b ? a = b, true : false; }
template<typename T> bool chmax(T &a, const T &b) { return a < b ? a = b, true : false; }

const int INF = 0x3f3f3f3f;

int solve() {
    int n; cin >> n;
    vector<int> l(n), r(n);
    vector<int> p; p.reserve(n * 4);
    for(int i = 0; i < n; ++i) cin >> l[i] >> r[i];
    for(int i = 0; i < n; ++i) {
        p.push_back(l[i]); p.push_back(r[i]);
        if(l[i] < r[i]) p.push_back(l[i] + 1), p.push_back(r[i] - 1);
    }
    
    sort(p.begin(), p.end());
    p.erase(unique(p.begin(), p.end()), p.end());
    
    int m = p.size();
    vector<int> d(m, 0);
    for(int i = 0; i < n; ++i) {
        for(int j = 0; j < m; ++j) if(l[i] <= p[j] && p[j] <= r[i]) {
            //
        } else {
            d[j] = INF;
        }
        int odd = INF, even = INF;
        for(int j = 0; j < m; ++j) {
            if(p[j] % 2 == 0) {
                chmin(d[j], p[j] / 2 + even);
                chmin(d[j], p[j] / 2 + odd);
                chmin(even, d[j] - p[j] / 2);
            } else {
                chmin(d[j], p[j] / 2 + even + 1);
                chmin(d[j], p[j] / 2 + odd);
                chmin(odd, d[j] - p[j] / 2);
            }
        }
        odd = even = INF + (int)1e9;
        for(int j = m - 1; j >= 0; --j) {
            if(p[j] % 2 == 0) {
                chmin(d[j], even - p[j] / 2);
                chmin(d[j], odd - p[j] / 2 + 1);
                chmin(even, d[j] + p[j] / 2);
            } else {
                chmin(d[j], even - p[j] / 2);
                chmin(d[j], odd - p[j] / 2);
                chmin(odd, d[j] + p[j] / 2);
            }
        }
    }
    return *min_element(d.begin(), d.end());
}

int main() {
    ios::sync_with_stdio(false);
    int T;
    cin >> T;
    while(T--) cout << solve() << endl;
    return 0;
}