#include<cstdio>

#include<algorithm>

#define ll long long

using namespace std;

inline ll read()

{

    ll sum = ,p = ;

    char ch = getchar();

    while(ch < '' || ch > '')

    {

        if(ch == '-')

            p = -;

        ch = getchar();

    }

    while(ch >= '' && ch <= '')

    {

        (sum *= ) += ch - '';

        ch = getchar();

    }

    return sum * p;

}

const int N = ;

const ll mod = ;

int n;

ll w[N],sum[N],ans;

int head[N],cnt;

struct edge

{

    int to,nxt;

}e[N];

void add(int a,int b)

{

    e[++cnt].nxt= head[a];

    e[cnt].to = b;

    head[a] = cnt;

}

void dfs(int u,int fa)

{

    sum[u] = w[u];

    for(int i = head[u];i;i = e[i].nxt)

    {

        int v = e[i].to;

        if(v == fa)

            continue;

        dfs(v,u);

        (sum[u] += sum[v])%= mod;

    }

}

void lcaa(int u,int fa)

{

    for(int i = head[u];i;i = e[i].nxt)

    {

        int v = e[i].to;

        if(v == fa)

            continue;

        ans = (ans + w[u]%mod * w[u]%mod * sum[v]%mod)%mod;

        ans = (ans + (sum[u] - w[u] - sum[v])%mod *w[u]%mod * sum[v]%mod)%mod;

        sum[u] = (sum[u] - sum[v] + mod)%mod;

    }

    for(int i = head[u];i;i = e[i].nxt)

    {

        int v = e[i].to;

        if(v == fa)

            continue;

        lcaa(v,u);

    }

}

int main()

{

    n = read();

    w[] = read();

    for(int i = ;i <= n;i++)

    {

        int fa = read();

        w[i] = read();

        add(fa,i);

        add(i,fa);

    }

    dfs(,);

    lcaa(,);

    ans = (ans * (ll)) % mod;

    for(int i = ;i <= n;i++)

        ans = (ans + w[i]%mod * w[i]% mod * w[i]%mod)%mod;

    printf("%lld",ans);

    return ;

}