// 那就是希望。
// 即便需要取模，也是光明。

#include <algorithm>
#include <queue>
#include <stdio.h>
#include <vector>
typedef long long llt;
typedef unsigned uint;typedef unsigned long long ullt;
typedef bool bol;typedef char chr;typedef void voi;
typedef double dbl;
template<typename T>bol _max(T&a,T b){return(a<b)?a=b,true:false;}
template<typename T>bol _min(T&a,T b){return(b<a)?a=b,true:false;}
template<typename T>T lowbit(T n){return n&-n;}
template<typename T>T gcd(T a,T b){return b?gcd(b,a%b):a;}
template<typename T>T lcm(T a,T b){return(a!=0||b!=0)?a/gcd(a,b)*b:(T)0;}
template<typename T>T exgcd(T a,T b,T&x,T&y){if(b!=0){T ans=exgcd(b,a%b,y,x);y-=a/b*x;return ans;}else return y=0,x=1,a;}
template<typename T>T power(T base,T index,T mod)
{
    T ans=1%mod;
    while(index)
    {
        if(index&1)ans=ans*base%mod;
        base=base*base%mod,index>>=1;
    }
    return ans;
}
// Heaven and Earth... My guiding star...
struct Info{
    llt A01,A02,A11,A12;
    friend Info operator*(Info a,Info b){
        Info ans;
        ans.A01=std::max(a.A01+b.A11,b.A01);
        ans.A02=std::max({a.A02,a.A01+b.A12,b.A02});
        ans.A11=a.A11+b.A11;
        ans.A12=std::max({a.A12,a.A11+b.A12});
        return ans;
    }
};
std::vector<uint>Way[100005];
uint Fath[100005],Siz[100005],Rot[100005],Dep[100005];
voi dfs(uint p,uint f)
{
    std::vector<uint>S;Siz[p]=1,Fath[p]=f;
    for(auto s:Way[p])if(s!=f)Dep[s]=Dep[p]+1,dfs(s,p),Siz[p]+=Siz[s],S.push_back(s);
    std::sort(S.begin(),S.end(),[&](uint a,uint b){return Siz[a]>Siz[b];}),Way[p]=S;
}
uint Fath_BST[100005],Son_BST[2][100005];Info W_BST[100005];llt Tag_BST[100005];
uint Fath_SonBST[100005],Rot_SonBST[100005],Son_SonBST[2][100005];
llt MaxV_SonBST[100005],SecMaxV_SonBST[100005],A[100005];
voi pushup_BST(uint p)
{
    auto&w=W_BST[p];
    w.A11=A[p];
    w.A01=w.A12=A[p]+(~Rot_SonBST[p]?MaxV_SonBST[Rot_SonBST[p]]:0);
    w.A02=A[p]+(~Rot_SonBST[p]?MaxV_SonBST[Rot_SonBST[p]]+SecMaxV_SonBST[Rot_SonBST[p]]:0);
    if(~Son_BST[0][p])w=W_BST[Son_BST[0][p]]*w;
    if(Tag_BST[p])w.A01+=Tag_BST[p],w.A02+=Tag_BST[p];
    if(~Son_BST[1][p])w=w*W_BST[Son_BST[1][p]];
}
uint build_BST(uint o,uint y)
{
    if(o==y)return-1;
    uint g=-1,m=-1;
    for(uint p=o;p!=y;p=Way[p].size()?Way[p][0]:-1u)
        if(_min(g,std::max(Siz[o]-Siz[p],(Way[p].size()?Siz[Way[p][0]]:0)-(~y?Siz[y]:0))))m=p;
    if(~(Son_BST[0][m]=build_BST(o,m)))Fath_BST[Son_BST[0][m]]=m;
    if(~(Son_BST[1][m]=build_BST(Way[m].size()?Way[m][0]:-1u,y)))Fath_BST[Son_BST[1][m]]=m;
    pushup_BST(m);Fath_BST[m]=-1;return m;
}
voi pushup_SonBST(uint p)
{
    MaxV_SonBST[p]=W_BST[p].A12,SecMaxV_SonBST[p]=0;
    if(~Son_SonBST[0][p])
    {
        if(MaxV_SonBST[Son_SonBST[0][p]]>MaxV_SonBST[p])
            _max(SecMaxV_SonBST[p]=MaxV_SonBST[p],SecMaxV_SonBST[Son_SonBST[0][p]]),
            MaxV_SonBST[p]=MaxV_SonBST[Son_SonBST[0][p]];
        else _max(SecMaxV_SonBST[p],MaxV_SonBST[Son_SonBST[0][p]]);
    }
    if(~Son_SonBST[1][p])
    {
        if(MaxV_SonBST[Son_SonBST[1][p]]>MaxV_SonBST[p])
            _max(SecMaxV_SonBST[p]=MaxV_SonBST[p],SecMaxV_SonBST[Son_SonBST[1][p]]),
            MaxV_SonBST[p]=MaxV_SonBST[Son_SonBST[1][p]];
        else _max(SecMaxV_SonBST[p],MaxV_SonBST[Son_SonBST[1][p]]);
    }
}
uint build_SonBST(std::vector<uint>&V,uint l,uint r)
{
    if(l==r)return-1;
    uint s=0,g=-1,m=-1;
    for(uint j=l;j<r;j++)s+=Siz[V[j]];
    for(uint j=l,t=0;j<r;t+=Siz[V[j++]])if(_min(g,std::max(t,s-=Siz[V[j]])))m=j;
    if(~(Son_SonBST[0][V[m]]=build_SonBST(V,l,m)))Fath_SonBST[Son_SonBST[0][V[m]]]=V[m];
    if(~(Son_SonBST[1][V[m]]=build_SonBST(V,m+1,r)))Fath_SonBST[Son_SonBST[1][V[m]]]=V[m];
    pushup_SonBST(V[m]);return V[m];
}
std::priority_queue<llt>Q1,Q2;
uint dfs2(uint p)
{
    uint r=p;
    while(~p)
    {
        Rot[p]=r,Fath_SonBST[p]=-1;
        if(Way[p].size())
        {
            std::vector<uint>S;for(uint j=1;j<Way[p].size();j++)S.push_back(dfs2(Way[p][j])),Fath_BST[S.back()]=p;
            if(~(Rot_SonBST[p]=build_SonBST(S,0,S.size())))Fath_SonBST[Rot_SonBST[p]]=-1;
            p=Way[p][0];
        }else Rot_SonBST[p]=-1,p=-1;
    }
    Q1.push(0);
    return build_BST(r,-1);
}
uint lca(uint u,uint v)
{
    while(Rot[u]!=Rot[v])
    {
        if(Dep[Rot[u]]<Dep[Rot[v]])std::swap(u,v);
        u=Fath[Rot[u]];
    }
    return Dep[u]<Dep[v]?u:v;
}
voi addA(uint p,llt w)
{
    uint q=p;
    while(~q)
    {
        if(!~Fath_BST[q]||(Son_BST[0][Fath_BST[q]]!=q&&Son_BST[1][Fath_BST[q]]!=q))
            Q2.push(std::max(W_BST[q].A01,W_BST[q].A02));
        q=Fath_BST[q];
    }
    A[p]+=w;
    while(~p)
    {
        pushup_BST(p);
        if(!~Fath_BST[p]||(Son_BST[0][Fath_BST[p]]!=p&&Son_BST[1][Fath_BST[p]]!=p))
        {
            Q1.push(std::max(W_BST[p].A01,W_BST[p].A02));
            q=p;while(~q)pushup_SonBST(q),q=Fath_SonBST[q];
        }
        p=Fath_BST[p];
    }
}
voi addB(uint p,llt w)
{
    uint q=p;
    while(~q)
    {
        if(!~Fath_BST[q]||(Son_BST[0][Fath_BST[q]]!=q&&Son_BST[1][Fath_BST[q]]!=q))
            Q2.push(std::max(W_BST[q].A01,W_BST[q].A02));
        q=Fath_BST[q];
    }
    bol ok=true;
    while(~p)
    {
        if(ok)Tag_BST[p]+=w;
        pushup_BST(p);
        if(!~Fath_BST[p]||(Son_BST[0][Fath_BST[p]]!=p&&Son_BST[1][Fath_BST[p]]!=p))
        {
            Q1.push(std::max(W_BST[p].A01,W_BST[p].A02)),ok=true;
            q=p;while(~q)pushup_SonBST(q),q=Fath_SonBST[q];
        }
        else ok=p==Son_BST[1][Fath_BST[p]];
        p=Fath_BST[p];
    }
}
int main()
{
#ifdef MYEE
    freopen("QAQ.in","r",stdin);
    freopen("QAQ.out","w",stdout);
#endif
    uint n,q;scanf("%u%u",&n,&q);
    for(uint i=1,u,v;i<n;i++)scanf("%u%u",&u,&v),Way[--u].push_back(--v),Way[v].push_back(u);
    dfs(0,-1),Fath_BST[dfs2(0)]=-1;
    for(uint t=0;t<q;t++)
    {
        static chr Op[5];static uint U[100005],V[100005];static llt W[100005];
        scanf("%s",Op);uint u,v;llt w;
        if(*Op=='+')scanf("%u%u%lld",&u,&v,&w),U[t]=--u,V[t]=--v,W[t]=w;else scanf("%u",&u),w=-W[--u],v=V[u],u=U[u];
        uint r=lca(u,v);addA(r,w),addB(u,w),addB(v,w),addB(r,-2*w);
        while(Q2.size()&&Q1.top()==Q2.top())Q1.pop(),Q2.pop();
        printf("%lld\n",Q1.top());
    }
    return 0;
}

// 那就是希望。
// 即便需要取模，也是光明。