#include <iostream>
#include <vector>
#include <climits>
#include <queue>

#define vpii vector<pair<int,int> >
#define vvi vector<vector<int> >

using namespace std;

int bfs(int i, vpii &bounds, vvi &dist, vector<int> &rights, int K) {
	pair<int, int> start = make_pair(i, bounds[i].first);
	queue<pair<int,int> > Q;
	Q.push(start);

	while(!Q.empty()) {
		pair<int,int> hf = Q.front();
		Q.pop();

		if (rights[hf.first] == hf.second) {
			return dist[hf.first][hf.second];
		}
		//cout << hf.first << " " << hf.second << ": " << dist[hf.first][hf.second] << endl;

		if (dist[hf.first][hf.second] + 1 < dist[hf.first][hf.second + 1]) {
			dist[hf.first][hf.second + 1] = dist[hf.first][hf.second] + 1;
			Q.push(make_pair(hf.first, hf.second + 1));
		}

		if (hf.first != K - 1 &&
			dist[hf.first][hf.second] + 1 < dist[hf.first + 1][hf.second]
		) {
			dist[hf.first + 1][hf.second] = dist[hf.first][hf.second] + 1;
			Q.push(make_pair(hf.first + 1, hf.second));
		}

		if (hf.first != 0 &&
			dist[hf.first][hf.second] + 1 < dist[hf.first - 1][hf.second]
		) {
			dist[hf.first - 1][hf.second] = dist[hf.first][hf.second] + 1;
			Q.push(make_pair(hf.first - 1, hf.second));
		}

	}

	return INT_MAX;
}

int main() {
	ios::sync_with_stdio(false);
	int N;
	cin >> N;		
	for(int NI = 0; NI < N; ++NI) {		
		int K;
		cin >> K;
		vector<int> rights;
		rights.resize(K + 1);

		vector<pair<int,int> > prev;
		prev.resize(K + 1);

		int maxB = 0;

		for(int KI = 0; KI < K; ++KI) {
			int l, r;
			cin >> l >> r;
			if (r > maxB) maxB = r;
			
			prev[KI] = make_pair(l,r);
			rights[KI] = r;
		}

		vector<vector<int> > dist;
		dist.resize(K);
		for(int i = 0; i < K; ++i) {			
			dist[i].resize(maxB + 1);
			dist[i][prev[i].first] = 0;
			for(int j = prev[i].first + 1; j < prev[i].second + 1; ++j) {
				dist[i][j] = j - prev[i].first + 1;
			}
		}

		int min = INT_MAX;
		for(int i = 0; i < K; ++i) {
			int m = bfs(i, prev, dist, rights, K);
			if (m < min) min = m;
		}
	
		cout << "K prechodu reky je treba " << min << " pontonu." << endl;
	}

	return 0;
}