#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
typedef long long ll;
const int N = 1e4, M = 1e5;
int n, m;
int a[N + 5];
vector<int> g[N + 5];


int dfn[N + 5], low[N + 5], cnt;
int st[N + 5], top, ins[N + 5];

vector<int> SCC[N + 5];
int tot, id[N + 5];

void tarjan(int u) {
    dfn[u] = low[u] = ++cnt;
    st[++top] = u;
    ins[u] = 1;
    for(int i = 0; i < g[u].size(); i++) {
        int v = g[u][i];
        if(!dfn[v]) {
            tarjan(v);
            low[u] = min(low[u], low[v]);
        } else if(ins[v]) {
            low[u] = min(low[u], dfn[v]);
        }
    }
    if(dfn[u] == low[u]) {
        tot++;
        int v;
        do {
            v = st[top--], ins[v] = 0;
            SCC[tot].push_back(v), id[v] = tot;
        } while(u != v);
    }
}


vector<int> g2[N + 5];
int a2[N + 5];
int in[N + 5];
queue<int> q;
int f[N + 5];

void topo() {
    while(!q.empty()) {
        int u = q.front();
        q.pop();
        for(int v : g2[u]) {
            f[v] = max(f[v], f[u] + a2[v]);
            in[v]--;
            if(!in[v]) {
                q.push(v);
            }
        }
    }
}


int main() {
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    cin >> n >> m;
    for(int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    for(int i = 1; i <= m; i++) {
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
    }
    tarjan(1);
    for(int k = 1; k <= tot; k++) {
        for(int u : SCC[k]) {
            a2[k] += a[u];
            for(int v : g[u]) {
                if(id[u] == id[v]) {
                    continue;
                }
                g2[id[u]].push_back(id[v]);
                in[id[v]]++;
            }
        }
    }
    for(int k = 1; k <= tot; k++) {
        if(!in[k]) {
            q.push(k);
        }
        f[k] = a2[k];
    }
    topo();
    int ans = 0;
    for(int k = 1; k <= tot; k++) {
        ans = max(ans, f[k]);
    }
    cout << ans << endl;
    return 0;
}