#include<iostream>

using namespace std;
const int N = 1e4 + 10;
int n, m, vol;
int p[N], v[N], w[N], f[N];

int find(int x) {
    if (x != p[x]) p[x] = find(p[x]);
    return p[x];
}

int main() {
    cin >> n >> m >> vol;

    for (int i = 1; i <= n; i++) p[i] = i;

    for (int i = 1; i <= n; i++) cin >> v[i] >> w[i];

    for (int i = 1; i <= m; i++) {
        int a, b;
        cin >> a >> b;
        int pa = find(a), pb = find(b);
        if (pa != pb) {
            w[pb] += w[pa];
            v[pb] += v[pa];
            p[pa] = p[pb];
        }
    }

    for (int i = 1; i <= n; i++) {
        if (p[i] == i)
            for (int j = vol; j >= v[i]; j--) {
                f[j] = max(f[j], f[j - v[i]] + w[i]);
            }
    }

    cout << f[vol] << endl;
}