function getGrpCnt(tree, node) {
    let cnt = 0;
    const children = tree[node];
    if (children) {
        delete tree[node];
        cnt++;
        for (const c of children) {
            cnt += getGrpCnt(tree, c);
        }
    }
    return cnt;
}

function journeyToMoon(n, astronaut) {
    const tree = {};
    for (const [a1, a2] of astronaut) {
        tree[a1] = tree[a1] ?? new Set();
        tree[a2] = tree[a2] ?? new Set();
        tree[a1].add(a2);
        tree[a2].add(a1);
    }

    let res = n * (n - 1) / 2;
    for (let a = 0; a < n; a++) {
        const cnt = getGrpCnt(tree, a);
        res -= cnt * (cnt - 1) / 2;
    }
    return res;
}