#include <bits/stdc++.h>
#define File(name) freopen(#name".in", "r", stdin); freopen(#name".out", "w", stdout);
using namespace std;
using ll = long long;
using ull = unsigned long long;
template<typename T>
inline T read(){
    T n = 0; int f = 1; char ch = getchar();
    while(!isdigit(ch)){
        if(ch == '-') f = -1;
        ch = getchar();
    }
    while(isdigit(ch)){
        n = n * 10 + ch - '0';
        ch = getchar();
    }
    return f * n;
}
template<typename T>
void write(T n){
    if(n < 0) return putchar('-'), write(-n);
    if(n / 10) write(n / 10);
    putchar(n % 10 + '0');
}
void input() {}
template<typename Type, typename... Types>
void input(Type &arg, Types &...args){
    arg = read<Type>();
    input(args...);
}
namespace Main{
    const int N = 105;
    int n, m, r, g[N][N], ans, bel[N];
    pair<int, int> mn[N];
    vector<int> vec;
    bool del[N], vis[N];
    void merge(int v, int u){
        bel[v] = u;
        vec.erase(find(vec.begin(), vec.end(), v));
        for(int i: vec) g[u][i] = min(g[u][i], g[v][i]);
        for(int i: vec) g[i][u] = min(g[i][u], g[i][v]);
    }
    void Main(){
        input(n, m, r);
        memset(g, 0x3f, sizeof(g));
        for(int i = 0, u, v, w; i < m; i++){
            input(u, v, w);
            g[u][v] = min(g[u][v], w);
        }
        vec.resize(n);
        iota(vec.begin(), vec.end(), 1);
        for(int i: vec) if(i != r){
            mn[i] = {1e9, -1};
            for(int j: vec) if(i != j) mn[i] = min(mn[i], make_pair(g[j][i], j));
            if(mn[i].second == -1) { puts("-1"); return; }
        }
        vis[r] = true;
        iota(bel + 1, bel + n + 1, 1);
        while(true){
            for(int i: vec) if(i != r) vis[i] = false, mn[i].second = bel[mn[i].second];
            bool ok = true;
            vector<int> _vec(vec);
            for(int i: _vec){
                if(i == r) continue;
                vector<int> path;
                int p = i;
                while(!vis[p]){
                    vis[p] = true;
                    path.push_back(p);
                    p = mn[p].second;
                }
                auto it = find(path.begin(), path.end(), p);
                if(it != path.end()){
                    ok = false;
                    int s = *it;
                    while(it != path.end()){
                        for(int j: vec) g[j][*it] -= mn[*it].first;
                        ans += mn[*it].first;
                        if(*it != s) merge(*it, s);
                        it++;
                    }
                    mn[s] = {1e9, -1};
                    for(int j: vec) if(j != s) mn[s] = min(mn[s], make_pair(g[j][s], j));
                    if(mn[s].second == -1) { puts("-1"); return; }
                }
            }
            if(ok){
                for(int i: vec) if(i != r) ans += mn[i].first;
                break;
            }
        }
        write(ans);
        return;
    }
} // namespace Main
int main(){
#ifdef Liuxizai
    freopen("in", "r", stdin);
    freopen("out", "w", stdout);
#endif // Liuxizai
    Main::Main();
    return 0;
}