int sz[N];
int parent[N];
int find_set(int v) {
    if (parent[v] == v) return v;
    return parent[v] = find_set(v);
}

int make_set(int v) {
    parent[v] = v;
    sz[v] = 1;
}

int union_sets(int u, int v) {
    v = find_set(v);
    u = find_set(u);
    if (u == v) return;
    if (sz[u] < sz[v]) swap(u, v);
    parent[v] = u;
    sz[u] += sz[v];
}