// zoltan chivay
// marigold
// triss


#include<iostream>
#include<cstdlib>
//#include<algorithm>
using namespace std;

int min (int a, int b) {
	return a < b ? a : b;
}

void printPl(int * pL, int k) {
	for (int i = 0; i < k; i++)
		cout << pL[i] << " ";
	cout << endl;
}

bool zaStartem (int x, int y, int* pS) {
	if (x <= pS[y])
		return false;
	return true;
}

bool zaCilem (int x, int y, int* pC) {
	if (x >= pC[y]) return true;
	return false;
}

int minNW (int y, int* pK, int* pL) {
	if (y == 0) return pK[y];
	else 
		return min (pK[y], pL[y-1]);	
}

int minSC (int y, int k, int * pL) {
	if (y == k-1) return pL[y];
	else return min(pL[y+1] + 1, pL[y]);
}


int main (int argc, char ** argv) {

int n;
cin >> n;

for (int mustafa = 0; mustafa < n; mustafa++) {
	int k;
	cin >> k;
	
	int * pS = new int[k];
	int * pC = new int[k];
	
	int maxX = -1;
	
	for (int i = 0; i < k; i++) {
		cin >> pS[i];
		cin >> pC[i];
		if (pC[i] > maxX) maxX = pC[i];
	}
	
	int minCost = 1000001;
	int * pK, * pL;
	pK = new int [k];
	for (int y = 0; y < k; y++)
		pK[y] = 0;
		
	for (int x = 1; x <= maxX; x++) {
		pL = new int[k];
		// prvni pruchod dolu
		for (int y = 0; y < k; y++) {
			if (! zaStartem(x, y, pS) )
				pL[y] = 0;
			else {
				pL[y] = minNW (y, pK, pL) + 1;
			}
		}
		// druhy pruchod nahoru
		for (int y = k-1; y >= 0; y--) {
			if (pL[y] != 0)
				pL[y] = minSC (y, k, pL);
			if (zaCilem(x, y, pC) && pL[y] < minCost)
				minCost = pL[y];
		}
		//printPl(pL, k);
		delete [] pK;
		pK = pL;
	}
	delete [] pK;
	delete [] pC;
	delete [] pS;
	cout << "K prechodu reky je treba " << minCost << " pontonu." << endl;
}

return 0;
}