static class Box {

int len;

int weight;

}

public static void main(String[] args)throws Exception{

Scanner in = new Scanner(new File("/home/mao/workspace/java/src/BiShi/pinduoduo4"));

while(in.hasNext()) {

int n = in.nextInt();

Box[] b = new Box[n+1];

b[0] = new Box();

for(int i = 1; i < n+1; ++i) {

b[i] = new Box();

b[i].len = in.nextInt();

}

for(int i = 1; i < n+1; ++i) {

b[i].weight = in.nextInt();

}

Arrays.sort(b, (b1, b2) -> {return b1.len == b2.len ? b1.weight-b2.weight : b1.len - b2.len;});

int res = 0;

int[][] dp = new int[n+1][n+1];

for(int i = 0; i < n+1; ++i) {

for(int j = 0; j < n+1; ++j) {

dp[i][j] = Integer.MAX_VALUE;

}

}

dp[0][0] = 0;

for(int i = 1; i < n+1; ++i) {

for(int k = 0; k < i; ++k) {

if(b[k].len < b[i].len) {

for(int j = 0; j <= k; ++j) {

if(dp[k][j] != Integer.MAX_VALUE && dp[k][j] <= b[i].weight*7) {

dp[i][j+1] = Math.min(dp[i][j+1], dp[k][j]+b[i].weight);

res = Math.max(res, j+1);

}

}

}

}

}

System.out.println(res);

}

}