#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <vector>
using namespace std;

const int N = 205, INF = 2e9, M = 1e6 + 5;

int n, m, r;
int pre[N];

vector<pair<int, int> > G[N];

bool vis[N];

int dfn[N], low[N], stk[N], in_stk[N], idx, cnt, top, id[N];
int u[M], v[M], w[M], minn[N];

void dfs(int u)
{
	vis[u] = true;
	for (int i = 0; i < G[u].size(); i++)
	{
		if (!vis[G[u][i].first])
		{
			dfs(G[u][i].first);
		}
	}
}

inline bool exist()
{
	dfs(r);
	for (int i = 1; i <= n; i++)
	{
		if (!vis[i]) return false;
	}
	return true;
}

void tarjan(int u)
{
	low[u] = dfn[u] = ++idx;
	stk[++top] = u, in_stk[u] = 1;
	int j = pre[u];
	if (!dfn[j])
	{
		tarjan(j);
		low[u] = min(low[u], low[j]);
	}
	else if (in_stk[j])
	{
		low[u] = min(low[u], dfn[j]);
	}
	if (dfn[u] == low[u])
	{
		cnt++;
		int y = 0;
		do
		{
			y = stk[top--];
			in_stk[y] = 0;
			id[y] = cnt;
		} while (y != u);
	}
}

int solve()
{
	int ans = 0;
	while (true)
	{
		memset(minn, 0x3f, sizeof minn);
		minn[r] = 0;
		for (int i = 1; i <= m; i++)
		{
			if (u[i] != v[i] && v[i] != r && w[i] < minn[v[i]])
			{
				minn[v[i]] = w[i];
				pre[v[i]] = u[i];
			}
		}
		memset(dfn, 0, sizeof dfn);
		idx = top = cnt = 0;
		for (int i = 1; i <= n; i++)
		{
			if (!dfn[i]) tarjan(i);
		}
		if (cnt == n)
		{
			for (int i = 1; i <= n; i++)
			{
				if (i != r) ans += minn[i];
			}
			break;
		}
		for (int i = 1; i <= n; i++)
		{
			if (i != r && id[pre[i]] == id[i])
			{
				ans += minn[i];
			}
		}
		for (int i = 1; i <= m; i++)
		{
			int rem = v[i];
			u[i] = id[u[i]], v[i] = id[v[i]];
			if (u[i] != v[i])
			{
				w[i] -= minn[rem];
			}
		}
		n = cnt;
		r = id[r];
	}
	return ans;
}

int main()
{
	scanf("%d%d%d", &n, &m, &r);
	for (int i = 1; i <= m; i++)
	{
		scanf("%d%d%d", &u[i], &v[i], &w[i]);
		G[u[i]].push_back(make_pair(v[i], w[i]));
	}
	if (!exist())
	{
		printf("-1\n");
	}
	else
	{
		printf("%d\n", solve());
	}
	return 0;
}

rt，全WA。