#include<bits/stdc++.h>usingnamespacestd;
usingLL = longlong;
constintN = 2005;
vector<int>e[N],t;
structasdf{vector<int> vec;
    LL val;
};
vector<asdf>w[N];
LL dp[N];
intn,m,k,dep[N]={1},f[N];
voiddfs(intu){
    for(autov:e[u])
    {
        dfs(v);
        dp[u]+=dp[v];
    }
    for(autot:w[u])
    {
        LL sum=dp[u];
        for(autonw:t.vec)
        {
            sum-=dp[nw];
            for(autov:e[nw]) sum+=dp[v];
        }
        dp[u]=max(dp[u],sum+t.val);
    }
}
intmain(){
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(0);
    cin>>n>>m;
    for(inti=2;i<=n;++i)
    {
        cin>>f[i];
        e[f[i]].push_back(i);
        dep[i]=dep[f[i]]+1;
    }
    for(inti=1,x,y;i<=m;++i)
    {
        LL val;
        cin>>x>>y>>val;
        t.clear();
        while(x!=y)
            if(dep[x]>dep[y]) t.push_back(x),x=f[x];
            elset.push_back(y),y=f[y];
        t.push_back(x);
        w[x].push_back({t,val});
    }
    dfs(1);
    cout<<dp[1];
    return0;
}

#include<bits/stdc++.h>usingnamespacestd;
usingLL=longlong;
intn,m;
constintN=2005;
structasdf{intx;
    LL val;
};
vector<asdf> w[N];
vector<int>e[N];
intdep[N];
LL dp[N][N];
voiddfs(intu){
    LL sum=0;
    for(inti=1;i<=dep[u];++i) dp[u][i]=1e18;
    for(autov:e[u])
    {
        dfs(v);
        sum+=dp[v][dep[u]+1];
        if(sum>=1e18)
        {
            cout<<-1;
            exit(0);
        }
        for(inti=1;i<=dep[u];++i)
            dp[u][i]=min(dp[u][i],dp[v][i]-dp[v][dep[u]+1]);
    }
    for(inti=1;i<=dep[u];++i) dp[u][i]+=sum;
    for(autov:w[u])
        dp[u][dep[v.x]]=min(dp[u][dep[v.x]],sum+v.val);
    for(inti=2;i<=dep[u];++i) dp[u][i]=min(dp[u][i],dp[u][i-1]);
}
intmain(){
    cin>>n>>m;
    dep[1]=1;
    for(inti=2;i<=n;++i)
    {
        intf;
        cin>>f;
        e[f].push_back(i);
        dep[i]=dep[f]+1;
    }
    for(inti=1;i<=m;++i)
    {
        intx,y;
        LL val;
        cin>>x>>y>>val;
        if(dep[x]>dep[y]) swap(x,y);
        w[y].push_back({x,val});
    }
    dfs(1);
    cout<<dp[1][1];
    return0;
}