Description：

Solution：

Code：

// luogu-judger-enable-o2

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstdio>

#include<cmath>

#include<queue>

#include<cstring>

#define INF 0x3f3f3f3f

using namespace std;

int n;

int s,t,tt;

struct edge

{

    int to,nxt,f,v;

}e[22010];

int edgenum = 0;

int lin[310];

inline void add(int a,int b,int c,int d)

{//cout << a << " " << b << " " << c << " " << d << endl;

	e[edgenum] = (edge){b,lin[a],c,d};lin[a] = edgenum++;

	e[edgenum] = (edge){a,lin[b],0,-d};lin[b] = edgenum++;

    return;

}

int d[310],rate[310],pre[310];

bool v[310];

int ind[310]; 

inline bool SPFA()

{

    memset(d,0x3f,sizeof(d));

    queue<int> q;

    q.push(s);

    d[s] = 0;

    rate[s] = INF;

    while(!q.empty())

    {

        register int k = q.front();q.pop();

        v[k] = false;

        for(register int i = lin[k];i != -1;i = e[i].nxt)

        {

            if(d[e[i].to] > d[k] + e[i].v && e[i].f)

            {

                d[e[i].to] = d[k] + e[i].v;

                rate[e[i].to] = min(rate[k],e[i].f);

                pre[e[i].to] = i;

                if(!v[e[i].to])

                {

                    v[e[i].to] = true;

                    q.push(e[i].to);

                }

            }

        }

    }

    return d[t] < INF;

}

inline int flow()

{

    for(register int i = t;i != s;i = e[pre[i] ^ 1].to)

    {//cout << i << endl;

        e[pre[i]].f -= rate[t];

        e[pre[i] ^ 1].f += rate[t];

    }//cout << s << endl;cout << rate[t] << " " << d[t] << endl;

    return rate[t] * d[t];

}

inline int EK()

{

    register int ans = 0;

    while(SPFA())ans += flow();

    return ans; 

}

inline int read()

{

    register int res = 0;

    register char c = getchar();

    while(!isdigit(c))c = getchar();

    while(isdigit(c))

    {

        res = (res << 3) + (res << 1) + c - '0';

        c = getchar();

    }

    return res;

}

int main()

{

    memset(lin,-1,sizeof(lin));

    scanf("%d",&n);

    tt = n + 1;s = tt + 1;t = s + 1;

    int sum = 0;

    register int k,x,y;

    for(register int i = 1;i <= n;++i)

    {

        k = read();

        add(i,tt,INF,0);

        for(register int j = 1;j <= k;++j)

        {

            x = read();y = read();

            add(i,x,INF,y);

            --ind[i];++ind[x];

            sum += y;

        }

    }

    for(register int i = 1;i <= n;++i)

    {

		if(ind[i] > 0)add(s,i,ind[i],0);

		if(ind[i] < 0)add(i,t,-ind[i],0);

	}

	add(tt,1,INF,0);

    cout << EK() + sum << endl;

    return 0;

}