#include <iostream>#include <cstdio>#include <cstring>#include <cstdlib>using namespace std;#define N 20005#define M 500005#define typec intconst typec inf = 0x3f3f3f3f;struct edge{ int x, y, nxt; typec c;} bf[M];int ne, head[N], cur[N], ps[N], dep[N];void addedge(int x, int y, typec c){ bf[ne].x = x; bf[ne].y = y; bf[ne].c = c; bf[ne].nxt = head[x]; head[x] = ne++; bf[ne].x = y; bf[ne].y = x; bf[ne].c = 0; bf[ne].nxt = head[y]; head[y] = ne++;}void addedge1(int x, int y, typec c){ bf[ne].x = x; bf[ne].y = y; bf[ne].c = c; bf[ne].nxt = head[x]; head[x] = ne++; bf[ne].x = y; bf[ne].y = x; bf[ne].c = c; bf[ne].nxt = head[y]; head[y] = ne++;}typec flow(int n, int s, int t){ typec tr, res = 0; int i, j, k, f, r, top; while (1) { memset(dep, -1, n * sizeof(int)); for (f = dep[ps[0] = s] = 0, r = 1; f != r;) { for (i = ps[f++], j = head[i]; j; j = bf[j].nxt) { if (bf[j].c && -1 == dep[k = bf[j].y]) { dep[k] = dep[i] + 1; ps[r++] = k; if (k == t) { f = r; break; } } } } if (-1 == dep[t]) break; memcpy(cur, head, n * sizeof(int)); for (i = s, top = 0;;) { if (i == t) { for (k = 0, tr = inf; k < top; ++k) if (bf[ps[k]].c < tr) tr = bf[ps[f = k]].c; for (k = 0; k < top; ++k) bf[ps[k]].c -= tr, bf[ps[k] ^ 1].c += tr; res += tr; i = bf[ps[top = f]].x; } for (j = cur[i]; cur[i]; j = cur[i] = bf[cur[i]].nxt) if (bf[j].c && dep[i] + 1 == dep[bf[j].y]) break; if (cur[i]) { ps[top++] = cur[i]; i = bf[cur[i]].y; } else { if (0 == top) break; dep[i] = -1; i = bf[ps[--top]].x; } } } return res;}int main(){ //freopen("D:\t.txt", "r", stdin); int n, m; scanf("%d%d", &n, &m); ne = 2; memset(head, 0, sizeof(head)); n += 2; int s = 0; int t = 1; for (int i = 2; i < n; i++) { int a, b; scanf("%d%d", &a, &b); addedge(s, i, a); addedge(i, t, b); } for (int i = 0; i < m; i++) { int x, y, c; scanf("%d%d%d", &x, &y, &c); addedge1(x + 1, y + 1, c); } printf("%dn", flow(n, s, t)); return 0;}
