[OpenJudge0054]特务会议召开

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <algorithm>
#include <set>
using namespace std;

int read() {
	int x = 0, f = 1; char c = getchar();
	while(!isdigit(c)){ if(c == ‘-‘) f = -1; c = getchar(); }
	while(isdigit(c)){ x = x * 10 + c - ‘0‘; c = getchar(); }
	return x * f;
}

#define maxn 100010
#define maxm 200010
#define maxlog 20
int n, q, m, head[maxn], nxt[maxm], to[maxm];

void AddEdge(int a, int b) {
	to[++m] = b; nxt[m] = head[a]; head[a] = m;
	swap(a, b);
	to[++m] = b; nxt[m] = head[a]; head[a] = m;
	return ;
}

int Dfs[maxn], clo, Poi[maxn], Fa[maxlog][maxn], dep[maxn];
void build(int u, int fa) {
	Dfs[u] = ++clo; Poi[clo] = u;
	Fa[0][u] = fa;
	for(int i = 1; i < maxlog; i++) Fa[i][u] = Fa[i-1][Fa[i-1][u]];
	for(int e = head[u]; e; e = nxt[e]) if(to[e] != fa) {
		dep[to[e]] = dep[u] + 1;
		build(to[e], u);
	}
	return ;
}

int calc(int a, int b) {
//	printf("in calc: %d %d\n", a, b);
	int ans = dep[a] + dep[b];
	if(dep[a] < dep[b]) swap(a, b);
	for(int i = maxlog - 1; i >= 0; i--)
		if(dep[a] - dep[b] >= (1 << i)) a = Fa[i][a];
	for(int i = maxlog - 1; i >= 0; i--)
		if(Fa[i][a] != Fa[i][b]) a = Fa[i][a], b = Fa[i][b];
	int c = a == b ? a : Fa[0][b];
	ans -= (dep[c] << 1);
	return ans;
}

set <int> S;
std :: set <int> :: iterator it, it2;

int main() {
	n = read(); q = read();
	for(int i = 1; i < n; i++) {
		int a = read(), b = read();
		AddEdge(a, b);
	}
	
	build(1, 0);
//	for(int i = 1; i <= n; i++) printf("(%d)%d ", i, Dfs[i]); putchar(‘\n‘);
//	for(int i = 1; i <= n; i++) printf("%d ", Poi[i]); putchar(‘\n‘);
	int ans = 0;
	while(q--) {
		char op[2]; scanf("%s", op);
		if(op[0] == ‘+‘) {
			int u = read();
			if(S.count(Dfs[u])) continue;
			if(S.size()) {
				it = S.upper_bound(Dfs[u]);
				int a = *it, b;
				if(it == S.end()) a = *(S.begin());
				if(it == S.begin()) {
					it2 = S.end();
					b = *(--it2);
				}
				else b = *(--it);
				a = Poi[a]; b = Poi[b];
				ans -= calc(a, b);
				ans += calc(a, u); ans += calc(u, b);
			}
			S.insert(Dfs[u]);
		}
		if(op[0] == ‘-‘) {
			int u = read();
			if(!S.count(Dfs[u])) continue;
			if(S.size()) {
				it = S.upper_bound(Dfs[u]);
				int a = *it, b;
				if(it == S.end()) a = *(S.begin());
				it = S.lower_bound(Dfs[u]);
				if(it == S.begin()) {
					it2 = S.end();
					b = *(--it2);
				}
				else {
					it2 = it;
					b = *(--it2);
				}
				a = Poi[a]; b = Poi[b];
				ans += calc(a, b);
				ans -= calc(a, u); ans -= calc(u, b);
			}
			S.erase(Dfs[u]);
		}
		if(op[0] == ‘?‘) printf("%d\n", ans >> 1);
	}
	
	return 0;
}
/*
13 1000
1 2
1 3
1 4
1 5
2 6
2 7
6 8
6 9
6 10
4 11
5 12
5 13
?
+ 13
?
+ 11
?
+ 9
?
*/