#include <bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
using namespace std;

using pii = pair<int, int>;
const int N = 5010, SZ = (1 << 18) + 5;
static char buf[SZ], *bgn = buf, *til = buf;
char getc() {
    if(bgn == til)  bgn = buf, til = buf + fread(buf, 1, SZ, stdin);
    return bgn == til ? EOF : *bgn++;
}
template<typename T>
void read(T &x) {
    char ch = getc();  T fh = 0;   x = 0;
    while(ch < '0' || ch > '9')    fh |= (ch == '-'), ch = getc();
    while(ch >= '0' && ch <= '9')   x = x * 10 + ch - '0', ch = getc();
    x = fh ? -x : x;
}
template<typename Type, typename... argc>
void read(Type &x, argc &...args)   {read(x), read(args...);}
template<typename T>
void print(T x) {
    if(x < 0)  putchar('-'), x = -x;
    if(x / 10)  print(x / 10);
    putchar(x % 10 + '0');
}
int n, u, v, m, a[N], cnt, fr[N], id[N], del[N], vis[N], fa[N], ans, sum, nxt[N], val[N], dis[N], que[N], hh, tt, idx;
vector<int> edge[N], cir[N], has[N], in[N];
bool g[N][N];
void clear() {
    for(int i = 1; i <= cnt; ++i)   cir[i].clear(), has[i].clear(), in[i].clear();
    for(int i = 1; i <= n; ++i) fr[i] = vis[i] = 0, edge[i].clear();
    cnt = ans = sum = idx = m = 0;
}
struct edges {int u, v, w;}edg[N * N];
void dfs(int x, int fath) {
    fa[x] = fath;
    for(int y : edge[x])    if(y != fath)   dfs(y, x);
}
void bfs(int str) {
    hh = 1, tt = 0;
    memset(dis, 0x3f, sizeof(dis)); 
    for(int x : has[str])   que[++tt] = x, dis[x] = 0;
    while(hh <= tt) {
        int x = que[hh++];
        if(fr[x] != str && !g[str][fr[x]])  edg[++m] = {str, fr[x], dis[x]}, g[str][fr[x]] = true;
        for(int y : edge[x])    
            if(dis[y] > dis[x] + 1) dis[y] = dis[x] + 1, que[++tt] = y;
    }
}
void dmst() {
    int n = cnt, root = 1;
    while(1) {
        for(int i = 1; i <= n; ++i) nxt[i] = id[i] = del[i] = 0, val[i] = N;
        memset(vis, 0, sizeof(vis));
        idx = 0;
        for(int i = 1; i <= m; ++i)
            if(edg[i].w < val[edg[i].v])    val[edg[i].v] = edg[i].w, nxt[edg[i].v] = edg[i].u;
        nxt[root] = 0, val[root] = N;
        int ct = 0;
        for(int i = 1; i <= n; ++i) if(i != root)   sum += val[i];
        for(int i = 1; i <= n; ++i) if(!vis[i]) {
            int x = i;  ++ct;
            while(x && !vis[x]) vis[x] = ct, x = nxt[x];
            if(x && vis[x] == ct) {
                id[x] = ++idx;  int nw = nxt[x];    del[x] = val[x];
                while(nw != x)  id[nw] = idx, nw = nxt[nw];
            }
        }
        if(!idx)    return;
        for(int i = 1; i <= n; ++i) if(!id[i])  id[i] = ++idx;
        int nm = 0;
        for(int i = 1; i <= m; ++i) 
            if(id[edg[i].u] != id[edg[i].v])    edg[++nm] = {id[edg[i].u], id[edg[i].v], edg[i].w - val[edg[i].v]};
        n = idx, m = nm, root = id[root];
    }
}
void mian() {
    read(n), clear();
    for(int i = 1; i <= n; ++i) read(a[i]);
    for(int i = 1; i < n; ++i)  read(u, v), edge[u].pb(v), edge[v].pb(u);
    for(int i = 1; i <= n; ++i) if((i == 1 || i != a[i]) && !vis[i]) {
        ++cnt;  int x = i;
        while(a[x] != i)    cir[cnt].pb(x), x = a[x];
        cir[cnt].pb(x);
        for(int j : cir[cnt])   vis[j] = 1, fr[j] = cnt;
    }
    for(int i = 1; i <= cnt; ++i) {
        cir[i].pb(cir[i][0]);
        memset(vis, 0, sizeof(vis));
        for(int j = 0; j + 1 < cir[i].size(); ++j) {
            dfs(cir[i][j + 1], 0);
            for(int x = cir[i][j]; x; x = fa[x]) {
                ++ans;
                if(!vis[x]) vis[x] = 1, has[i].pb(x);
            }
            --ans;
        }
    }
    for(int i = 1; i <= cnt; ++i)   memset(g[i], 0, sizeof(g[i]));
    for(int i = 1; i <= cnt; ++i)   bfs(i);
    // cerr << cnt << "\n";
    dmst();
    // cerr << ans << " " << sum << "\n";
    print(ans + sum * 2), putchar('\n');
}
int main() {
    #ifdef Kelly
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
        freopen("err.txt", "w", stderr);
    #else
        // freopen("classic.in", "r", stdin);
        // freopen("classic.out", "w", stdout);
    #endif
    int T = 1; // read(T);
    while(T--)  mian();
    return 0;
}