#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstdlib>
#include<fstream>
using namespace std;
long long a[100005];
double b[100005];
double dp[10005];
int main()
{
	long long n,m;
	while(~scanf("%lld %lld",&n,&m))
	{
		if(n==0&&m==0)
		{
			break;
		}
        long long i,j;
        for(i=0;i<10005;i++)
        {
        	dp[i]=1;
		}
        for(i=1;i<=m;i++)
        {
        	scanf("%lld %lf",&a[i],&b[i]);
		}
		for(i=1;i<=m;i++)
		{
			for(j=n;j>=a[i];j--)
			{
				dp[j]=min(dp[j],dp[j-a[i]]*(1-b[i]));
			}
		}
		printf("%.1lf%%\n",(1-dp[n])*100);
	}
	return 0;
}