use ac_library::MfGraph;
use proconio::{input, marker::Usize1};

fn main() {
    input! {
        n: usize, m: usize,
        ab: [(i64, i64); n],
        uvc: [(Usize1, Usize1, i64); m],
    }

    let mut graph = MfGraph::new(n + 2);
    let (src, sink) = (n, n + 1);

    let mut ans = 0;
    for (i, &(a, b)) in ab.iter().enumerate() {
        ans += a + b;
        graph.add_edge(src, i, a);
        graph.add_edge(i, sink, b);
    }

    for &(u, v, c) in &uvc {
        graph.add_edge(u, v, c);
        graph.add_edge(v, u, c);
    }

    ans -= graph.flow(src, sink);
    println!("{ans}");
}