#1369 : 网络流一·Ford-Fulkerson算法 模板题

#include <bits/stdc++.h>
#define IOS ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;
const int maxn = 500 + 20;
int e[maxn][maxn];
int pre[maxn], flow[maxn];
int n, m;
int bfs(int be, int en) {
    queue<int> que;
    memset(pre, false, sizeof pre);
    pre[be] = -1, flow[be] = inf;
    que.push(be);
    while (!que.empty()) {
        int id = que.front();
        que.pop();
        if (id == en) break; // 找到增广路径
        for (int i = 1; i <= n; ++i) {
            if (pre[i] == 0 && e[id][i] > 0) {
                pre[i] = id;
                flow[i] = min(flow[id], e[id][i]);
                que.push(i);
            }
        }
    }
    if (pre[en] == 0) return -1;
    else return flow[en];
}
int maxFlow(int be, int en) {
    int sumFlow = 0;
    while (true) {
        int res = bfs(be, en);
        if (res == -1) break; //找不到增广路
        int u = pre[en], v = en;
        while (u != -1) {
            e[u][v] -= res;
            e[v][u] += res;
            v = u;
            u = pre[v];
        }
        sumFlow += res;
    }
    return sumFlow;
}
void work() {
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= m; ++i) {
        int u, v, w;
        scanf("%d%d%d", &u, &v, &w);
        e[u][v] += w;
    }
    cout << maxFlow(1, n) << endl;
}

int main() {
#ifdef local
    freopen("data.txt", "r", stdin);
//    freopen("data.txt", "w", stdout);
#endif
    work();
    return 0;
}