#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 500000
int min(int a, int b) { return a < b ? a : b; }
int max(int a, int b) { return a > b ? a : b; }
int *ej[N], eo[N];
void append(int i, int j) {
int o = eo[i]++;
if (o >= 2 && (o & o - 1) == 0)
ej[i] = (int *) realloc(ej[i], o * 2 * sizeof *ej[i]);
ej[i][o] = j;
}
int aa[N], pp[N], ta[N], tb[N], ll[N], rr[N], ll_[N], rr_[N];
void dfs1(int p, int i) {
static int time;
int o;
pp[i] = p,
ta[i] = time++;
for (o = eo[i]; o--; ) {
int j = ej[i][o];
if (j != p)
dfs1(i, j);
}
tb[i] = time;
}
char cut[N];
void dfs2(int p, int i) {
int o;
ll_[i] = ll[aa[i]], rr_[i] = rr[aa[i]];
for (o = eo[i]; o--; ) {
int j = ej[i][o];
if (j != p) {
dfs2(i, j);
ll_[i] = min(ll_[i], ll_[j]), rr_[i] = max(rr_[i], rr_[j]);
cut[j] = ta[j] <= ll_[j] && rr_[j] < tb[j];
}
}
}
int ds[N];
int find(int i) {
return ds[i] < 0 ? i : (ds[i] = find(ds[i]));
}
void join(int i, int j) {
i = find(i);
j = find(j);
if (i == j)
return;
if (ds[i] > ds[j])
ds[i] = j;
else {
if (ds[i] == ds[j])
ds[i]--;
ds[j] = i;
}
}
int main() {
static int dd[N];
int n, k, h, i, j, l;
scanf("%d%d", &n, &k);
for (i = 0; i < n; i++)
ej[i] = (int *) malloc(2 * sizeof *ej[i]);
for (h = 0; h < n - 1; h++) {
scanf("%d%d", &i, &j), i--, j--;
append(i, j), append(j, i);
}
for (i = 0; i < n; i++)
scanf("%d", &aa[i]), aa[i]--;
dfs1(-1, 0);
memset(ll, 0x3f, n * sizeof *ll), memset(rr, -1, n * sizeof *rr);
for (i = 0; i < n; i++)
ll[aa[i]] = min(ll[aa[i]], ta[i]), rr[aa[i]] = max(rr[aa[i]], ta[i]);
dfs2(-1, 0);
memset(ds, -1, n * sizeof *ds);
for (i = 1; i < n; i++)
if (!cut[i])
join(i, pp[i]);
for (i = 1; i < n; i++)
if (cut[i])
dd[find(i)]++, dd[find(pp[i])]++;
l = 0;
for (i = 0; i < n; i++)
if (dd[i] == 1)
l++;
printf("%d\n", (l + 1) / 2);
return 0;
}
