#include <cstdio>
#include <algorithm>
#include <cstring>

using namespace std;

#define MAXN 1011

typedef pair<int, int> pii;

//a means ans
//x -> [l, r]
int To(int a[], int& n, int x, int l, int r) {
    if (l <= x && x <= r) {
        a[n++] = x;
        return 0;
    } else if (x < l) {
        a[n++] = l;
        if (((l - x) & 1) && l < r) {
            a[n++] = l + 1;
        }
        return (l - x + 1) >> 1;
    } else {    //x > r
        a[n++] = r;
        if (((x - r) & 1) && l < r) {
            a[n++] = r - 1;
        }
        return (x - r + 1) >> 1;
    }
}
int Solve(int to[], int& len, int from[], int n, int l, int r) {
    int ans = 0x3f3f3f3f;
    len = 0;
    for (int i = 0; i < n; ++i) {
        static int now[100];
        int nl = 0;
        int t = To(now, nl, from[i], l, r);
        if (t > ans) continue;
        if (t < ans) {
            ans = t;
            len = 0;
        }
        while (nl) {
            --nl;
            to[len++] = now[nl];
        }
    }
    return ans;
}

pii Cross(pii x, pii y) {
    return make_pair(max(x.first, y.first), min(x.second, y.second));
}
int main() {
    int T;
    static int a[MAXN], b[MAXN];

    static int base[2][MAXN * 4];

    scanf("%d", &T);
    while (T--) {
        int n;

        scanf("%d", &n);
        for (int i = 0; i < n; ++i) {
            scanf("%d%d", a+i, b+i);
        }

        int *from = base[0], *to = base[1];
        pii ori(1, 1000000);
        int i;
        for (i = 0; i < n; ++i) {
            auto now(Cross(make_pair(a[i], b[i]), ori));
            if (now.first > now.second)
                break;
            ori = now;
        }

        int len = 0;
        from[len++] = ori.first;
        from[len++] = ori.second;
        if (ori.first < ori.second) {
            from[len++] = ori.second - 1;
            from[len++] = ori.first + 1;
        }

        int ans = 0;
        for (; i < n; ++i) {
            sort(from, from + len);
            len = unique(from, from + len) - from;
            int tolen;
            ans += Solve(to, tolen, from, len, a[i], b[i]);
            swap(to, from);
            swap(len, tolen);
        }
        printf("%d\n", ans);
    }

    return 0;
}