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#include <cstdio>
#include <string>
#include <cmath>
#include <cstring>
#include <vector>

using namespace std;

const int N = 600000;

vector<int> g[N];
int prevs[N];
int room[N];

int qh[2], qt[2], q[2][N];

inline void push(int id, int value) {
    q[id][qt[id]++] = value;
}

inline bool empty(int id) {
    return qh[id] == qt[id];
}

inline int pop(int id) {
    return q[id][qh[id]++];
}

int solve(int n, int m, int cur) {
    fill(prevs, prevs + n, 0);

    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < g[i].size(); ++j) {
            ++prevs[g[i][j]];
        }
    }

    qh[0] = qt[0] = qh[1] = qt[1] = 0;
    for (int i = 0; i < n; ++i) {
        if (prevs[i] == 0) {
            push(room[i], i);
        }
    }
    int taken = 0;
    int ans = 0;
    while (true) {
        while (!empty(cur)) {
            int u = pop(cur);
            ++taken;
            for (int i = 0; i < g[u].size(); ++i) {
                int v = g[u][i];
                if (--prevs[v] == 0) {
                    push(room[v], v);
                }
            }
        }
        if (taken == n) {
            break;
        }
        cur = 1 - cur;
        ++ans;
    }
    return ans;
}

int main() {
    //freopen("in.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    for (int i = 0; i < t; ++i) {
        int n, m;
        scanf("%d %d", &n, &m);
        for (int j = 0; j < n; ++j) {
            g[j].resize(0);
        }
        for (int j = 0; j < n; ++j) {
            scanf("%d", &room[j]);
            --room[j];
        }
        for (int j = 0, u, v; j < m; ++j) {
            scanf("%d %d", &u, &v);
            --u, --v;
            g[u].push_back(v);
        }
        printf("%d\n", min(solve(n, m, 0), solve(n, m, 1)));
    }
    return 0;
}