#include <bits/stdc++.h>
using namespace std;
int n,m,w;
struct node
{
	int v,w;
};
vector<node> g[10005];
int fa[10005],c[10005],d[10005],summ[10005],sumv[10005];
int w0[10005],v[10005],dp[3][10005];
bool f[10005];
int find(int x)
{
	if(x == fa[x])return x;
	return fa[x] = find(fa[x]);
}
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> m >> w;
	for(int i = 1;i <= n;i++)
	{
		fa[i] = i;
		cin >> c[i] >> d[i];
	}
	for(int i = 1;i <= m;i++)
	{
		int a,b;
		cin >> a >> b;
		int one = find(a);
		int two = find(b);
		if(one == two)continue;
		fa[one] = two;
	}
	for(int i = 1;i <= n;i++)
	{
		summ[find(i)] += c[i];
		sumv[find(i)] += d[i];
	}
	int cur = 0;
	for(int i = 1;i <= n;i++)
	{
		if(!f[find(i)])
		{
			cur++;
			w0[cur] = summ[find(i)];
			v[cur] = sumv[find(i)];
		}
	}
	for(int i = 1;i <= cur;i++)
	{
		for(int j = 0;j <= w;j++)
		{
			if(j < w0[i])
			{
				dp[i%2][j] = dp[(i-1)%2][j];
			}
			else
			{
				dp[i%2][j] = max(dp[(i-1)%2][j],dp[(i-1)%2][j-w0[i]]+v[i]);
			}
		}
	}
	cout << dp[cur%2][w];
	return 0;
}

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