#include <stdio.h>
#include <stdlib.h>
#include <string.h>
double gailv[10001], f[10001], tmp;
int jiage[10001];
int main()
{
int n,m,i,k;
while(scanf("%d%d", &n, &m) != NULL){
if (n == 0 && m == 0 )
return 0;
for(i=0; i<m; i++)
scanf("%d%lf", &jiage[i], &gailv[i]);
memset(f, 0, sizeof(f));
for(i=0;i<m;++i){
for(k=n;k>=jiage[i];--k)
f[k] = 1 - ((1 - f[k - jiage[i]])*(1 - gailv[i]));
}
tmp = 0;
for (i=0;i<=n;++i)
if(tmp<f[i])
tmp = f[i];
printf("%.1lf%%\n", tmp*100);
}
return 0;
}