#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
const int N=100,inf=1e9;
int n=26,m,h[N],cnt=1,s=1,t=26,le[N],x;
char s1[5],s2[5];
struct qwe
{
    int ne,to,va;
}e[N*N*2];
void add(int u,int v,int w)
{
    cnt++;
    e[cnt].ne=h[u];
    e[cnt].to=v;
    e[cnt].va=w;
    h[u]=cnt;
}
void ins(int u,int v,int w)
{
    add(u,v,w);
    add(v,u,0);
}
bool bfs()
{
    memset(le,0,sizeof(le));
    queue<int>q;
    q.push(s);
    le[s]=1;
    while(!q.empty())
    {
        int u=q.front();
        q.pop();
        for(int i=h[u];i;i=e[i].ne)
            if(!le[e[i].to]&&e[i].va>0)
            {
                le[e[i].to]=le[u]+1;
                q.push(e[i].to);
            }
    }
    return le[t];
}
int dfs(int u,int f)
{
    if(u==t||!f)
        return f;
    int us=0;
    for(int i=h[u];i&&us<f;i=e[i].ne)
        if(le[e[i].to]==le[u]+1&&e[i].va>0)
        {
            int t=dfs(e[i].to,min(e[i].va,f-us));
            e[i].va-=t;
            e[i^1].va-=t;
            us+=t;
        }
    if(!us)
        le[u]=0;
    return us;
}
int dinic()
{
    int re=0;
    while(bfs())
        re+=dfs(s,inf);
    return re;
}
int main()
{
    scanf("%d",&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%s%s%d",s1,s2,&x);
        ins(s1[0]-'A'+1,s2[0]-'A'+1,x);
    }
    printf("%d\n",dinic());
    return 0;
}