C++ :

#define MAX(A,B) ((A)>(B)?(A):(B))
#define MIN(A,B) ((A)<(B)?(A):(B))
#define MAXN 110
#include<cstdio>
#include<cstring>

using namespace std;

int n, m, t, num, head, cnt, dnf[MAXN], low[MAXN], d[MAXN], w[MAXN], v[MAXN], ru[MAXN], sta[MAXN], bg[MAXN], wt[MAXN], my[MAXN], ch[MAXN][2], f[MAXN][510];
bool ins[MAXN], vis[MAXN];

struct me {
	int qian, hou, nt;
}sg[MAXN];

void ADD(int x,int y) {
	sg[++t].hou = y;
	sg[t].qian = x;
	sg[t].nt = d[x];
	d[x] = t;
}
void TARJAN(int x) {
	vis[x] = true;
	low[x] = dnf[x] = ++num;
	sta[++head] = x;
	ins[x] = true;
	for(int i = d[x] ; i != -1 ; i = sg[i].nt) {
		if(!vis[sg[i].hou]) {
			TARJAN(sg[i].hou);
			low[x] = MIN(low[x], low[sg[i].hou]);
		} else {
			if(ins[sg[i].hou]) {
				low[x] = MIN(low[x], dnf[sg[i].hou]);
			}
		}
	}
	if(low[x] == dnf[x]) {
		int op;
		++cnt;
		do {
			op = sta[head--];
			//printf("%d belong to -> %d\n", op, cnt);
			ins[op] = false;
			bg[op] = cnt;
		} while(op!=x);
	}
	return;
}

void DP(int x,int k) {
	if(!x&&k) {
		return;
	}
	DP(ch[x][1], k+1);
	DP(ch[x][0], k+1);
	if(m>wt[x]) {
		for(int i = 1 ; i < wt[x] ; ++ i) {
			f[x][i] = f[ch[x][1]][i];
		}
		f[x][wt[x]] = MAX(my[x], f[ch[x][1]][wt[x]]);
		for(int i = wt[x]+1 ; i <= m ; ++ i) {
			f[x][i] = MAX(f[x][i-1], f[ch[x][1]][i]);
			for(int j = 0 ; j <= i-wt[x] ; ++ j) {
				f[x][i] = MAX(f[x][i], f[ch[x][0]][j]+f[ch[x][1]][i-wt[x]-j]+my[x]);
			}
		//	printf("f[%d][%d] = %d\n", x, i, f[x][i]);
		}
	} else {
		for(int i = 1 ; i <= m ; ++ i) {
			f[x][i] = f[ch[x][1]][i];
		}
		if(m==wt[x]) {
			f[x][m] = MAX(f[x][m], my[x]);
		}
	}
}

int main() {
	int x;
	memset(d, -1, sizeof(d));
	scanf("%d%d", &n, &m);
	for(int i = 1 ; i <= n ; ++ i) {
		scanf("%d", &w[i]);
	}
	for(int i = 1 ; i <= n ; ++ i) {
		scanf("%d", &v[i]);
	}
	for(int i = 1 ; i <= n ; ++ i) {
		scanf("%d", &x);
		if(x) {
			ADD( x, i);
		}
	}
	for(int i = 1 ; i <= n ; ++ i) {
		if(!vis[i]) {
			TARJAN(i);
		}
	}
	for(int i = 1 ; i <= n ; ++ i) {
		my[bg[i]] += v[i];
		wt[bg[i]] += w[i];
	}
	int nu = 0;
	for(int i = 1 ; i <= t ; ++ i) {
		if(bg[sg[i].qian]!=bg[sg[i].hou]) {
		    ++nu;
			++ru[bg[sg[i].hou]];
			if(ch[bg[sg[i].qian]][0]) {
				int q = ch[bg[sg[i].qian]][0], p;
				while(q) {
					p = q;
					q = ch[q][1];
				}
				ch[p][1] = bg[sg[i].hou];
			} else {
				ch[bg[sg[i].qian]][0] = bg[sg[i].hou];
			}
		}
	}
	for(int i = 1 ; i <= cnt ; ++ i) {
		if(!ru[i]) {
			++nu;
			if(!ch[0][0]) {
				ch[0][0] = i;
			} else {
				int q= ch[0][0], p;
				while(q) {
					p = q;;
					q = ch[q][1];
				}
				ch[p][1] = i;
			}
		}
	}
	DP(0,0);
	printf("%d", f[ch[0][0]][m]);
	getchar();
	getchar();
	return 0;
}