'''
先用并查集缩点，然后进行01背包DP
'''

import sys
sys.setrecursionlimit(99999999)


class MergeSetExt:
    def __init__(self, max_key_val = 0, trans_key_func=None):
        if trans_key_func is not None and max_key_val > 0:
            # 如果能够提供转换key的回调，并查集内部用线性表存储
            self.trans_key_callback = trans_key_func
            self.m = [-1 for _ in range(max_key_val+1)]
            self.__root2cluster_size = [0 for _ in range(max_key_val+1)]
        else:
            # 如果不能提供转换key的回调，并查集内部用hash表存储
            self.trans_key_callback = None
            self.m = {}
            self.__root2cluster_size = {}
        self.__root_cnt = 0

    def getRoot(self, node):
        buf = []
        root = self.trans_key_callback(node) if self.trans_key_callback else node
        while self.m[root] != root:
            buf.append(root)
            root = self.m[root]
        for key in buf:
            self.m[key] = root

        return root

    def merge(self, a, b):
        orig_a, orig_b = a, b
        if self.trans_key_callback:
            a, b = self.trans_key_callback(a), self.trans_key_callback(b)

        for node in [a, b]:
            if (self.trans_key_callback is None and node not in self.m) or (self.trans_key_callback is not None and self.m[node] == -1):
                self.m[node] = node
                self.__root2cluster_size[node] = 1
                self.__root_cnt += 1

        root1 = self.getRoot(orig_a)
        root2 = self.getRoot(orig_b)
        if root1 != root2:
            self.m[root1] = root2

            self.__root2cluster_size[root2] += self.__root2cluster_size[root1]
            if self.trans_key_callback:
                self.__root2cluster_size[root1] = 0
            else:
                self.__root2cluster_size.pop(root1)
            self.__root_cnt -= 1

    # 根据根节点的数值获取其所在的簇的大小
    def getClusterSize(self, root):
        return self.__root2cluster_size[root]

    def isInSameSet(self, a, b):
        if a == b:
            return True

        orig_a, orig_b = a, b
        if self.trans_key_callback:
            a, b = self.trans_key_callback(a), self.trans_key_callback(b)

            for node in [a, b]:
                if self.m[node] == -1:
                    return False
        else:
            for node in [orig_a, orig_b]:
                if node not in self.m:
                    return False

        return self.getRoot(orig_a) == self.getRoot(orig_b)

    def getRootNum(self):
        return self.__root_cnt

    def getClusters(self):
        rec = {}
        if self.trans_key_callback is None:
            for node in self.m:
                root = self.getRoot(node)
                if root not in rec:
                    rec[root] = []
                rec[root].append(node)
        else:
            for node in range(len(self.m)):
                if self.m[node] == -1:
                    continue

                root = self.getRoot(node)
                if root not in rec:
                    rec[root] = []
                rec[root].append(node)

        return [nodes for nodes in rec.values()]


n, m, w = map(int, input().split())

val = [0] * (n+1)
cost = [0] * (n+1)
for i in range(1, n+1):
    s = sys.stdin.readline()
    cost[i], val[i] = map(int, s.split())

merge_set = MergeSetExt(max_key_val=n, trans_key_func=lambda x : x)
for i in range(1, n+1):
    merge_set.merge(i, i)
for i in range(m):
    s = sys.stdin.readline()
    a, b = map(int, s.split())
    merge_set.merge(a, b)


ans = 0
arr = []
for cluster in merge_set.getClusters():

    total_cost, total_val = 0, 0
    for node in cluster:
        total_cost += cost[node]
        total_val += val[node]

    if total_cost <= w:
        arr.append((total_cost, total_val))

# 01 背包
if len(arr) == 0:
    print(0)
else:
    dp = [0] * (w + 1)
    for i in range(len(arr)):
        for j in range(w, -1, -1):
            if i == 0:
                dp[j] = arr[i][1] if j >= arr[i][0] else 0
            else:
                if j >= arr[i][0]:
                    dp[j] = max(dp[j], arr[i][1] + dp[j - arr[i][0]])

    print(dp[w])