#include <cassert>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cctype>

#include <algorithm>
#include <functional>
#include <set>
#include <map>
#include <vector>
#include <iostream>
#include <limits>
#include <numeric>

#define LOG(FMT...) fprintf(stderr, FMT)

using namespace std;

const int N = 1010;

int n;
int t[N], b[N];
int dp[N][1 << 8][17];

void upd(int& a, int y) {
	if (a > y || a == -1)
		a = y;
}

void solve() {
	scanf("%d", &n);
	for (int i = 1; i <= n; ++i)
		scanf("%d%d", t + i, b + i);
	memset(dp, -1, sizeof(dp));
	for (int i = 1; i <= n; ++i)
		b[i] = min(b[i], n - i);
	for (int i = 0; i <= b[1]; ++i)
		dp[1][1 << i][i + 8] = 0;
	for (int i = 1; i <= n; ++i) {
		for (int j = 0; j < 256; ++j) {
			int top = -1;
			while (j >> (top + 1))
				++top;
			bool f = true;
			for (int k = 0; k < top; ++k)
				if (!(j >> k & 1) && top > k + b[i + k]) {
					f = false;
					break;
				}
			if (!f)
				continue;
			for (int k = -8; k <= 7; ++k) {
				if (dp[i][j][k + 8] == -1)
					continue;
				if (j & 1)
					upd(dp[i + 1][j >> 1][k + 7], dp[i][j][k + 8]);
				else
					for (int l = 0; l <= b[i]; ++l)
						if (!(j >> l & 1))
							upd(dp[i][j | 1 << l][l + 8], dp[i][j][k + 8] + (t[i + l] ^ t[i + k]));
			}
		}
	}
	int ans = -1;
	for (int i = 0; i <= 8; ++i)
		if (ans == -1 || (ans > dp[n][1][i] && dp[n][1][i] != -1))
			ans = dp[n][1][i];
	printf("%d\n", ans);

}

int main() {
#ifndef ONLINE_JUDGE
	freopen("test.in", "r", stdin);
	int nol_cl = clock();
#endif

	int c;
	scanf("%d", &c);
	while (c--)
		solve();

#ifndef ONLINE_JUDGE
	LOG("Time: %dms\n", int((clock() - nol_cl) / (double)CLOCKS_PER_SEC * 1000));
#endif
	return 0;
}