#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
#define min(a,b) ((a)<(b)?(a):(b))
#define N 10010

int w[N];
double dp[N];
double v[N];

int main()
{
    int n,s,i,j;
    while(scanf("%d%d",&s,&n),n||s)
    {
        for(i=1;i<=n;i++)
        {
            scanf("%d%lf",&w[i],&v[i]);
            v[i]=1-v[i];
        }
        for(i=0;i<=N;i++) //从0开始啊，白贡献WA
        {
            dp[i]=1;
        }
        for(i=1;i<=n;i++)
        {
            for(j=s;j>=w[i];j--)
            {
                dp[j]=min(dp[j],dp[j-w[i]]*v[i]);
            }
        }
        printf("%.1f%%\n",(1-dp[s])*100);
    }
    return 0;
}