#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

const int N = 1e4 + 5;
template <typename T>
struct Stack
{
    T s[N]; int tp;
    Stack() { tp = 0; }
    void push(T x) { s[++tp] = x; }
    void pop() { tp--; }
    T top() { return s[tp]; }
};

int a[N];
vector<int> G[N];
int dfn[N], low[N], scc[N], sc;
bool ins[N];
int sum[N], dp[N];

void tarjan(int u)
{
    static int cur = 0;
    static Stack<int> s;

    dfn[u] = low[u] = ++cur;
    s.push(u); ins[u] = true;

    for (int v : G[u])
        if (!dfn[v]) tarjan(v), low[u] = min(low[u], low[v]);
        else if (ins[v])        low[u] = min(low[u], dfn[v]);

    if (low[u] != dfn[u]) return;
    sc++;
    while (ins[u])
    {
        int t = s.top();
        ins[t] = false;
        scc[t] = sc;
        sum[sc] += a[t];
        for (int v : G[t])
            dp[sc] = max(dp[sc], dp[ scc[v] ]);
        dp[sc] += sum[sc];
        s.pop();
    }
}

int main()
{
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1, u, v; i <= m; i++)
        cin >> u >> v, G[u].push_back(v);
    for (int i = 1; i <= n; i++)
        if (!dfn[i]) tarjan(i);
    cout << *max_element(dp + 1, dp + sc + 1);
}