#include<stdio.h>
int f[10][100];
int package(int *w,int *v,int n,int c)
{
int i,j;
for(i=1;i<=n;i++)
f[i][0] = 0;
for(j=1;j<=c;j++)
f[0][j] = 0;
for(i=1;i<=n;i++)
{
for(j=1;j<=c;j++)
{
if(w[i] <= j && f[i-1][j-w[i]] + v[i] > f[i-1][j])
{
f[i][j] = f[i-1][j-w[i]] + v[i];
}else
f[i][j] = f[i-1][j];
}
}
return f[n][c];
}
int main()
{
int i,j;
int m,n;
scanf("%d %d",&m,&n);
int g[100];
int value[100];
for(i = 1 ;i<= n;i++)
{
scanf("%d",&g[i]);
}
for(i = 1 ;i<= n;i++)
{
scanf("%d",&value[i]);
}
int SumValue = package(g,value,n,m);
float cat = SumValue * 0.1;
printf("%.1fn",cat);
}