3 10
2 3 1
1 1
3 3
3 3
3 2
1 1
2 2
3 1
1 3
2 1
3 3
 7 20
6 2 5 7 3 1 4
7 7
1 1
2 2
6 1
4 4
2 2
2 2
6 6
3 5
7 4
1 6
4 4
6 1
1 1
3 3
5 3
3 5
5 3
2 2
4 4
 4 20
4 2 3 1
2 2
1 4
2 2
1 1
3 3
3 3
1 4
3 3
2 2
3 3
4 1
2 2
1 4
3 3
4 1
1 1
3 3
2 2
2 2
4 4
 9 6
9 2 3 4 5 6 7 8 1
1 4
4 7
2 5
5 8
3 6
6 9
 7 20
5 6 2 1 7 4 3
1 4
5 4
7 5
7 4
2 4
6 5
1 5
3 3
1 5
6 2
7 3
4 1
6 4
7 5
7 3
1 5
1 3
6 6
5 2
5 7
 3 1
3 2 1
1 2
 8 20
8 4 7 2 6 5 3 1
6 6
2 4
7 3
4 2
3 3
6 5
6 5
8 8
3 7
6 6
7 3
4 4
1 8
1 8
3 7
8 8
6 6
2 4
8 8
4 2
 3 2
1 3 2
1 3
3 1
 20 20
4 12 7 1 16 19 3 10 14 8 13 2 11 9 20 5 18 17 6 15
9 14
3 3
8 10
7 3
20 20
5 16
13 11
6 19
6 6
12 2
12 2
13 11
18 18
18 17
9 14
8 8
20 15
4 4
16 16
4 1
 9 20
6 7 9 1 3 4 8 2 5
8 2
2 7
1 6
6 1
6 1
3 3
9 5
8 2
8 2
9 5
4 1
5 5
9 3
9 3
6 6
7 8
4 6
7 8
1 1
8 2
 5 20
2 4 1 5 3
1 4
3 1
4 5
1 1
4 2
3 2
4 4
1 2
4 5
5 5
5 5
2 2
2 5
5 3
5 5
3 3
5 1
2 2
4 5
1 5
 4 20
3 4 1 2
2 4
4 4
3 1
3 1
4 4
3 3
4 4
1 1
4 4
4 2
3 3
1 3
1 3
2 2
1 3
1 1
3 1
2 4
4 4
2 4
 6 20
5 3 2 4 1 6
3 2
5 5
3 2
4 4
4 4
4 4
5 1
3 2
3 2
1 1
6 6
6 6
6 6
4 4
6 6
1 5
1 1
5 1
2 2
2 3
 83 8
54 3 52 12 61 36 65 62 69 49 47 77 31 15 21 14 73 29 6 26 37 17 81 75 43 30 58 76 16 8 11 5 27 35 7 66 50 67 2 39 45 28 60 71 38 82 53 1 42 13 44 72 22 4 9 25 19 57 10 70 18 68 32 34 20 80 23 79 24 63 64 51 59 41 74 48 40 33 46 83 55 56 78
48 80
1 8
71 54
15 59
72 46
36 9
64 29
55 58
 1 1
1
1 1
 5 20
3 4 1 5 2
2 4
3 1
2 2
4 5
4 5
5 2
1 1
2 4
3 3
4 2
3 1
1 1
5 2
1 3
3 1
4 2
1 3
3 3
4 2
4 2
 6 20
4 6 1 3 2 5
2 2
6 5
3 4
3 4
5 6
3 3
5 5
6 6
4 3
2 2
2 2
5 2
3 4
1 4
5 2
4 3
2 5
1 4
3 1
4 3
 2 10
1 2
1 1
2 2
2 2
1 1
1 1
2 2
2 2
1 1
2 2
1 1
 5 3
5 2 3 4 1
2 4
1 4
3 4
 4 1
4 3 1 2
3 4
 3 1
1 3 2
1 2
 2 10
2 1
2 1
1 2
1 1
2 1
1 1
2 1
1 1
1 1
2 1
2 1
 3 1
2 3 1
1 1
 8 1
3 4 1 2 7 8 5 6
3 4
 3 10
1 2 3
2 2
1 1
2 2
3 3
1 1
3 3
3 3
3 3
2 2
1 1

3 2 1 
 6 2 5 7 3 1 4 
 4 2 3 1 
 9 8 6 7 5 3 4 2 1 
 7 6 5 4 3 2 1 
 3 2 1 
 8 4 7 2 6 5 3 1 
 2 3 1 
 4 12 7 1 16 19 3 10 14 8 13 2 11 9 20 5 18 17 6 15 
 6 8 9 4 5 1 7 2 3 
 5 4 3 2 1 
 3 4 1 2 
 5 3 2 4 1 6 
 62 3 52 12 61 36 65 54 69 49 47 77 31 15 21 14 73 29 6 26 37 17 81 75 43 30 58 76 34 8 11 5 27 35 7 66 50 67 2 39 45 28 60 71 38 82 53 83 42 13 44 72 22 64 57 25 19 9 10 70 18 68 32 16 20 80 23 79 24 63 4 51 59 41 74 48 40 33 46 1 55 56 78 
 1 
 3 5 1 4 2 
 4 6 3 1 5 2 
 1 2 
 5 4 3 2 1 
 4 3 2 1 
 3 1 2 
 2 1 
 2 3 1 
 3 4 2 1 7 8 5 6 
 1 2 3 

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <queue>
#include <deque>
#include <bitset>
#include <iterator>
#include <list>
#include <stack>
#include <map>
#include <set>
#include <functional>
#include <numeric>
#include <utility>
#include <climits>
#include <iomanip>
#include <unordered_map>
#include <unordered_set>
#include <time.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
using namespace std;
#define ll long long 
#define pb push_back
#define fio ios_base::sync_with_stdio(false);cin.tie();cout.tie();
constexpr long long  MOD=1000000007;
ll add(ll x, ll y) {ll res = x + y; return (res >= MOD ? res - MOD : res);}
ll mul(ll x, ll y) {ll res = x * y; return (res >= MOD ? res % MOD : res);}
ll sub(ll x, ll y) {ll res = x - y; return (res < 0 ? res + MOD : res);}
ll lcm(ll x, ll y) {ll res = (x * y) / __gcd(x, y); return res;}
ll power(ll x, ll y) {if (y < 0) return 1; ll res = 1; x %= MOD; while (y) {if (y & 1)res = mul(res, x); y >>= 1; x = mul(x, x);} return res;}

void iofoj(){
	#ifndef ONLINE_JUDGE
	freopen("input.txt","r",stdin);
	freopen("output.txt","w",stdout);
	freopen("error.txt","w",stderr);
	#endif
}
ll color[300004];
ll black[300004];
ll red[300004];
bool visi[300004];
vector<ll>v[300004];
ll r,b,ans;

void dfs(ll u)
{
    visi[u]=true;
    if(color[u]==1)
    {
        red[u]+=1;
    }
    else if(color[u]==2)
    {
        black[u]+=1;
    }
    for(auto i:v[u])
    {
        if(visi[i]==false)
        {
            dfs(i);
            red[u]+=red[i];
            black[u]+=black[i];
        }
    }
}

void dfs2(ll u)
{
    visi[u]=true;
    for(auto i:v[u])
    {
        if(visi[i]==false)
        {
            if(black[i]==0)
            {
                if(red[i]==r)ans++;
            }
            else if(red[i]==0)
            {
                if(black[i]==b)ans++;
            }
            dfs2(i);
        }
    }

}

void solution()
{
    ll q,n,m,i,j,k;
    cin>>n;
    r=0;
    b=0;
    for(i=1;i<=n;i++)
    {
        cin>>color[i];
        visi[i]=false;
        black[i]=0;
        red[i]=0;
        if(color[i]==1)r++;
        else if(color[i])b++;
    }
    for(i=0;i<n-1;i++)
    {
        cin>>j>>k;
        v[j].pb(k);
        v[k].pb(j);
    }
    dfs(1);
    ans=0;
    for(i=1;i<=n;i++)
    {
        visi[i]=false;
    }
    dfs2(1);
    cout<<ans;
}

int main(){
    fio
    //iofoj();
    // ll t;
    // cin>>t;
    // while(t--)
    solution();
    return 0; 
}