#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

#include<cctype>

inline long long read(){

    long long num=,f=;

    char ch=getchar();

    while(!isdigit(ch)){

        if(ch=='-')    f=-;

        ch=getchar();

    }

    while(isdigit(ch)){

        num=num*+ch-'';

        ch=getchar();

    }

    return num*f;

}

struct Edge{

    int next,to,val;

}edge[];

int head[],num=-;

inline void add(int from,int to,int val){

    edge[++num]=(Edge){    head[from],to,val};

    head[from]=num;

}

bool vis[];

int dfn[];

int f[],h,t=;

int n,m,Start,End;

bool bfs(){

    memset(vis,,sizeof(vis));

    f[]=Start;vis[Start]=;dfn[Start]=;h=;t=;

    while(h++<t){

        int from=f[h];

        for(int i=head[from];i!=-;i=edge[i].next){

            int to=edge[i].to;

            if(vis[to]||(!edge[i].val))    continue;

            dfn[to]=dfn[from]+;

            vis[to]=;

            f[++t]=to;

        }

    }

    return vis[End];

}

int dfs(int x,int val){

    if(x==End)    return val;

    vis[x]=;

    for(int i=head[x];i!=-;i=edge[i].next){

        int to=edge[i].to;

        if(dfn[to]==dfn[x]+&&!vis[to]&&edge[i].val>){

            int now=dfs(to,std::min(edge[i].val,val));

            if(now>){

                edge[i].val-=now;

                edge[i^].val+=now;

                return now;

            }

        }

    }

}

int ans;

int main(){

    memset(head,-,sizeof(head));

    n=read(),m=read(),Start=read(),End=read();

    for(int i=;i<=m;++i){

        int from=read(),to=read(),val=read();

        add(from,to,val);

        add(to,from,);

    }

    while(bfs()){

        memset(vis,,sizeof(vis));

        int now=dfs(Start,0x7fffffff);

        if(!now)    break;

        ans+=now;

    }

    printf("%d",ans);

    return ;

}