F - I NEED A OFFER!

#include<cstdio>
#include<cstring>
#include<iostream>
#include<stdlib.h>
#include<vector>
#include<queue>
#include<cmath>
using namespace std;
#define maxn 25055
#define oo 0x3f3f3f
int n;
int k;
double dp[maxn];
struct point
{
    int a;
    double b;
} p[maxn];
double  max(double x,double y)
{
    if(x>y)
        return x;
    else
        return y;
}
int main()
{
    int t,n,m;

    while(scanf("%d%d", &n,&m),n||m)
    {
        memset(dp, 0, sizeof(dp));


        for(int i=1; i<=m; i++)
        {
            scanf("%d%lf",&p[i].a,&p[i].b);
        }



        for(int i=1; i<=m; i++)
        {
            for(int j=n; j>=p[i].a; j--)
            {
                dp[j] = max(dp[j],1-(1-dp[j-p[i].a])*(1-p[i].b));
            }
        }

        double ans = dp[n]*100;
        printf("%.1f",ans);
        printf("%%\n");

    }

    return 0;
}