#include<bits/stdc++.h>
using namespace std;

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

#define mygc(c) (c)=getchar_unlocked()
#define mypc(c) putchar_unlocked(c)

#define ll long long
#define ull unsigned ll

void reader(int *x){int k,m=0;*x=0;for(;;){mygc(k);if(k=='-'){m=1;break;}if('0'<=k&&k<='9'){*x=k-'0';break;}}for(;;){mygc(k);if(k<'0'||k>'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);}
void reader(int *x, int *y){reader(x);reader(y);}
void writer(int x, char c){int s=0,m=0;char f[10];if(x<0)m=1,x=-x;while(x)f[s++]=x%10,x/=10;if(!s)f[s++]=0;if(m)mypc('-');while(s--)mypc(f[s]+'0');mypc(c);}

int T, N;
int C[2000], V[2000];
int dp[10001];

int main(){
  int i, j, k, m;

  reader(&T, &N);
  rep(i,N) reader(C+i);
  rep(i,N) reader(V+i);

  m = N;
  rep(i,N){
    j = C[i];
    k = V[i];
    for(;;){
      k /= 2;
      if(k==0) break;
      C[m] = j;
      V[m++] = k;
    }
  }
  N = m;

  rep(k,N) for(i=T-C[k];i>=0;i--) dp[i+C[k]] = max(dp[i+C[k]], dp[i]+V[k]);
  writer(dp[T], '\n');

  return 0;
}