#include <iostream>
#include <fstream>
#include <stdio.h>
#include <math.h>

using namespace std;

struct play
{
	int g;
	double p;
};

int n, m;
play *plays;

double prob( int yards )
{
	double eff = 0.0;
	int mostEff = 0;
	for( int i = 0; i < m; i++ )
	{
		int geff = plays[i].g;
		if( geff > yards )
		{
			geff = yards;
		}
		double nextEff = pow( 1.0 * plays[i].p, 1.0 * yards / geff );
		if( nextEff > eff )
		{
			eff = nextEff;
			mostEff = i;
		}
	}
	double pr = pow( plays[mostEff].p, yards / plays[mostEff].g );
	if( yards > plays[mostEff].g * ( yards / plays[mostEff].g ) )
	{
		return ( pr * prob( yards % plays[mostEff].g ) );
	}
	else
	{
		return pr;
	}
	return 0.0;
}


int main( void )
{
	ifstream fin;
	fin.open( "football.in" );
	int k;
	fin >> k;
	for( int setNum = 1; setNum <= k; setNum++ )
	{
		cout << "Data Set " << setNum << ":\n";
		fin >> n >> m;
		plays = new play[m];
		for( int i = 0; i < m; i++ )
		{
			fin >> plays[i].g >> plays[i].p;
		}
		printf( "%.2f\n", prob( n ) );
	}
	fin.close();
	return 0;
}