#include<bits/stdc++.h>
#define ll long long
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rof(i,a,b) for(int i=(a);i>=(b);--i)
using namespace std;
const int Maxn=1e5,Maxk=5e5;

inline int read()
{
    int x=0,f=1;
    char ch=getchar();
    while(ch<'0' || ch>'9')
    {
        if(ch=='-') f=-1;
        ch=getchar();
    }
    while(ch>='0' && ch<='9')
    {
        x=x*10+ch-'0';
        ch=getchar();
    }
    return x*f;
}

int n,m,X,Y,id[Maxn+5]; ll ans[Maxk+5],dep[Maxn+5];
int vis[Maxn+5],siz[Maxn+5],maxs[Maxn+5],rt,sum;
vector<pair<int,int>> v[Maxn+5];
vector<array<int,3>> w[Maxn+5];

struct Tree
{
    int fa[Maxn+5],st[Maxn+5][20],dfn[Maxn+5],cur; ll dis[Maxn+5];
    vector<pair<int,int>> v[Maxn+5];
    inline int GetID(int x,int y) {return dfn[x]<dfn[y]?x:y;}
    inline void dfs(int x,int f)
    {
        fa[x]=f,dfn[x]=++cur,st[cur][0]=f;
        for(auto [y,z]:v[x]) if(y!=f) dis[y]=dis[x]+z,dfs(y,x);
    }
    inline int LCA(int x,int y)
    {
        if(x==y) return x; if((x=dfn[x])>(y=dfn[y])) swap(x,y);
        int len=__lg(y-x++); return GetID(st[x][len],st[y-(1<<len)+1][len]);
    }
    inline ll Dis(int x,int y) {return dis[x]+dep[x]+dis[y]+dep[y]-2*dis[LCA(x,y)];}
    inline void Insert(int p)
    {
        if(X==-1) {X=p; return;} if(Y==-1) {Y=p; return;}
        ll a=Dis(X,Y),b=Dis(X,p),c=Dis(Y,p);
        if(b>a && b>=c) Y=p; else if(c>a && c>b) X=p;
    }
    inline void Init()
    {
        For(i,1,n-1)
        {
            int a=read(),b=read(),c=read();
            v[a].emplace_back(b,c),v[b].emplace_back(a,c);
        } dfs(1,0);
        For(j,1,19) for(int i=1;i+(1<<j)-1<=n;++i)
            st[i][j]=GetID(st[i][j-1],st[i+(1<<j-1)][j-1]);
    }
} T;

inline void GetRt(int x,int f)
{
    siz[x]=1,maxs[x]=0; for(auto [y,z]:v[x]) if(y!=f && !vis[y])
        GetRt(y,x),siz[x]+=siz[y],maxs[x]=max(maxs[x],siz[y]);
    maxs[x]=max(maxs[x],sum-siz[x]);
    if(maxs[x]<maxs[rt]) rt=x;
}
inline void dfs(int x,int f,ll d,int p) {dep[x]=d,id[x]=p; for(auto [y,z]:v[x]) if(y!=f && !vis[y]) dfs(y,x,d+z,p);}
inline void dfs1(int x,int f) {T.Insert(x); for(auto [y,z]:v[x]) if(y!=f && !vis[y]) dfs1(y,x);}
inline void Work(int x,vector<array<int,3>> qr)
{
    dep[x]=0,id[x]=x,X=x,Y=-1; for(auto [y,z]:v[x]) if(!vis[y])
        dfs(y,x,z,y),vector<array<int,3>>().swap(w[y]);
    for(auto i:qr) w[id[i[0]]].push_back(i);
    for(auto [y,z]:v[x]) if(!vis[y])
    {
        for(auto [a,b,id]:w[y])
        {
            if(X!=-1) ans[id]=max(ans[id],dep[a]-dep[b]+T.Dis(b,X));
            if(Y!=-1) ans[id]=max(ans[id],dep[a]-dep[b]+T.Dis(b,Y));
        } dfs1(y,x);
    }
    for(auto [a,b,id]:w[x])
    {
        if(X!=-1) ans[id]=max(ans[id],dep[a]-dep[b]+T.Dis(b,X));
        if(Y!=-1) ans[id]=max(ans[id],dep[a]-dep[b]+T.Dis(b,Y));
    }
    X=x,Y=-1,reverse(v[x].begin(),v[x].end());
    for(auto [y,z]:v[x]) if(!vis[y])
    {
        for(auto [a,b,id]:w[y])
        {
            if(X!=-1) ans[id]=max(ans[id],dep[a]-dep[b]+T.Dis(b,X));
            if(Y!=-1) ans[id]=max(ans[id],dep[a]-dep[b]+T.Dis(b,Y));
            // printf("%d: %d %d %lld %lld %lld\n",x,X,Y,dep[a],dep[b],dep[Y]);
        } dfs1(y,x);
    }
}
inline void dfs(int x,vector<array<int,3>> qr)
{
    vis[x]=1; Work(x,qr); for(auto [y,z]:v[x]) if(!vis[y])
        rt=0,sum=siz[y],GetRt(1,0),GetRt(rt,0),dfs(rt,w[y]);
}

int main()
{
    // freopen("1.in","r",stdin);

    n=read(),m=read();
    For(i,1,n-1)
    {
        int a=read(),b=read(),c=read();
        v[a].emplace_back(b,c),v[b].emplace_back(a,c);
    }
    T.Init(); vector<array<int,3>> qr;
    For(i,1,m) {int a=read(),b=read(); qr.push_back({a,b,i});}
    maxs[0]=n+5,rt=0,sum=n,GetRt(1,0),GetRt(rt,0),dfs(rt,qr);
    For(i,1,m) printf("%lld\n",ans[i]);
    return 0;
}