#include <bits/stdc++.h>
using namespace std;
int l[5050], r[5050];
long long f[5010], g[5010];
typedef long long LL;
LL as(LL a) { return (abs(a) + 1) / 2; }
int main() {
#ifdef TEST
    freopen("input.txt", "r", stdin);
#endif
    int T;
    scanf("%d", &T);
    while (T--) {
        int n;
        scanf("%d", &n);
        vector<int> all;
        for (int i = 0; i < n; ++i) {
            scanf("%d%d", &l[i], &r[i]);
            all.push_back(l[i]);
            all.push_back(r[i]);
            all.push_back(l[i] + 1);
            all.push_back(r[i] - 1);
        }
        sort(all.begin(), all.end());
        all.resize(unique(all.begin(), all.end()) - all.begin());
        for (int i = 0; i < all.size(); ++i) {
            f[i] = 0;
        }
        for (int i = 0; i < n; ++i) {
            l[i] = lower_bound(all.begin(), all.end(), l[i]) - all.begin();
            r[i] = lower_bound(all.begin(), all.end(), r[i]) - all.begin();
            for (int i = 0; i < all.size(); ++i) {
                g[i] = 1e9 + 7;
            }
            for (int j = 0; j < all.size(); ++j) {
                if (l[i] <= j && j <= r[i]) {
                    g[j] = min(g[j], f[j]);
                }
                g[l[i]] = min(g[l[i]], f[j] + as(all[j] - all[l[i]]));
                g[r[i]] = min(g[r[i]], f[j] + as(all[j] - all[r[i]]));
                if (l[i] < r[i]) {
                    int l = ::l[i] + 1;
                    int r = ::r[i] - 1;
                    g[l] = min(g[l], f[j] + as(all[j] - all[l]));
                    g[r] = min(g[r], f[j] + as(all[j] - all[r]));
                }
            }
            for (int i = 0; i < all.size(); ++i) {
                f[i] = g[i];
            }
        }
        printf("%lld\n", *min_element(f, f + all.size()));
    }
    return 0;
}