# 最小カットバージョン import sys # sys.setrecursionlimit(200005) int1 = lambda x: int(x)-1 pDB = lambda *x: print(*x, end="\n", file=sys.stderr) p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr) def II(): return int(sys.stdin.readline()) def LI(): return list(map(int, sys.stdin.readline().split())) def LLI(rows_number): return [LI() for _ in range(rows_number)] def LI1(): return list(map(int1, sys.stdin.readline().split())) def LLI1(rows_number): return [LI1() for _ in range(rows_number)] def SI(): return sys.stdin.readline().rstrip() dij = [(0, 1), (-1, 0), (0, -1), (1, 0)] # dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)] inf = (1 << 63)-1 # inf = (1 << 31)-1 md = 10**9+7 # md = 998244353 from typing import NamedTuple, Optional, List, cast class MFGraph: class Edge(NamedTuple): src: int dst: int cap: int flow: int class _Edge: def __init__(self, dst: int, cap: int) -> None: self.dst = dst self.cap = cap self.rev: Optional[MFGraph._Edge] = None def __init__(self, n: int) -> None: self._n = n+2 self._g: List[List[MFGraph._Edge]] = [[] for _ in range(n+2)] self._edges: List[MFGraph._Edge] = [] self._lower_sum = 0 def add_edge(self, src: int, dst: int, cap: int) -> int: assert 0 <= src < self._n assert 0 <= dst < self._n assert 0 <= cap m = len(self._edges) e = MFGraph._Edge(dst, cap) re = MFGraph._Edge(src, 0) e.rev = re re.rev = e self._g[src].append(e) self._g[dst].append(re) self._edges.append(e) return m # cap's range [l,r] def add_edge_lr(self, src: int, dst: int, l: int, r: int) -> int: assert 0 <= src < self._n assert 0 <= dst < self._n assert 0 <= l <= r if r-l: self.add_edge(src, dst, r-l) self.add_edge(src, self._n-1, l) self.add_edge(self._n-2, dst, l) self._lower_sum += l def add_undir_edge(self, src: int, dst: int, cap: int) -> int: assert 0 <= src < self._n assert 0 <= dst < self._n assert 0 <= cap m = len(self._edges) e = MFGraph._Edge(dst, cap) re = MFGraph._Edge(src, cap) e.rev = re re.rev = e self._g[src].append(e) self._g[dst].append(re) self._edges.append(e) return m def get_edge(self, i: int) -> Edge: assert 0 <= i < len(self._edges) e = self._edges[i] re = cast(MFGraph._Edge, e.rev) return MFGraph.Edge( re.dst, e.dst, e.cap+re.cap, re.cap ) def edges(self) -> List[Edge]: return [self.get_edge(i) for i in range(len(self._edges))] def change_edge(self, i: int, new_cap: int, new_flow: int) -> None: assert 0 <= i < len(self._edges) assert 0 <= new_flow <= new_cap e = self._edges[i] e.cap = new_cap-new_flow assert e.rev is not None e.rev.cap = new_flow def flow(self, s: int, t: int, flow_limit: Optional[int] = None) -> int: assert 0 <= s < self._n assert 0 <= t < self._n assert s != t if flow_limit is None: flow_limit = cast(int, sum(e.cap for e in self._g[s])) current_edge = [0]*self._n level = [0]*self._n def fill(arr: List[int], value: int) -> None: for i in range(len(arr)): arr[i] = value def bfs() -> bool: fill(level, self._n) queue = [] q_front = 0 queue.append(s) level[s] = 0 while q_front < len(queue): v = queue[q_front] q_front += 1 next_level = level[v]+1 for e in self._g[v]: if e.cap == 0 or level[e.dst] <= next_level: continue level[e.dst] = next_level if e.dst == t: return True queue.append(e.dst) return False def dfs(lim: int) -> int: stack = [] edge_stack: List[MFGraph._Edge] = [] stack.append(t) while stack: v = stack[-1] if v == s: flow = min(lim, min(e.cap for e in edge_stack)) for e in edge_stack: e.cap -= flow assert e.rev is not None e.rev.cap += flow return flow next_level = level[v]-1 while current_edge[v] < len(self._g[v]): e = self._g[v][current_edge[v]] re = cast(MFGraph._Edge, e.rev) if level[e.dst] != next_level or re.cap == 0: current_edge[v] += 1 continue stack.append(e.dst) edge_stack.append(re) break else: stack.pop() if edge_stack: edge_stack.pop() level[v] = self._n return 0 flow = 0 while flow < flow_limit: if not bfs(): break fill(current_edge, 0) while flow < flow_limit: f = dfs(flow_limit-flow) flow += f if f == 0: break return flow def flow_lr(self, s: int, t: int, flow_limit: Optional[int] = None) -> int: assert 0 <= s < self._n assert 0 <= t < self._n assert s != t if flow_limit: flow_limit -= self._lower_sum if flow_limit < 0: return -1 f = self.flow(self._n-2, self._n-1)*2 f += self.flow(self._n-2, t) f += self.flow(s, self._n-1) if f < self._lower_sum*2: return -1 f = self.flow(s, t, flow_limit) return f+self._lower_sum def min_cut(self, s: int) -> List[bool]: visited = [False]*self._n stack = [s] visited[s] = True while stack: v = stack.pop() for e in self._g[v]: if e.cap > 0 and not visited[e.dst]: visited[e.dst] = True stack.append(e.dst) return visited n = II() ans = 0 mf = MFGraph(2*n+2) s, t = 2*n, 2*n+1 for u in range(n): b, c = LI() mx = max(b, c) ans += mx mf.add_edge(u*2, u*2+1, mx) if mx-b: mf.add_edge(s, u*2, mx-b) if mx-c: mf.add_edge(u*2+1, t, mx-c) for _ in range(II()): u, v = LI() mf.add_edge(v*2+1, u*2, inf) ans -= mf.flow(s, t) print(ans)