#include <bits/stdc++.h>
using namespace std;

void allTopologicalSort(vector<char> &cur, int *cnt, unordered_map<char, bool> &visited,
                        unordered_map<char, int> &inDegree, unordered_map<char, vector<char>> &adj)
{
    bool flag = false;
    for (auto [ch, vec] : adj)
    {
        if (inDegree[ch] == 0 && visited[ch] == false)
        {
            for (auto nei : adj[ch])
            {
                inDegree[nei]--;
            }
            cur.push_back(ch);
            visited[ch] = true;
            allTopologicalSort(cur, cnt, visited, inDegree, adj);
            ;

            visited[ch] = false;
            cur.erase(cur.end() - 1);

            for (auto nei : adj[ch])
            {
                inDegree[nei]--;
            }

            flag = true;
        }
    }

    if (flag == false)
    {
        (*cnt)++;
    }
}

string LineOrdering(vector<string> &inputs)
{
    unordered_map<char, vector<char>> adj;
    unordered_map<char, int> inDegree;
    for (string input : inputs)
    {
        if (input[1] == '>')
        {
            adj[input[0]].push_back(input[2]);
            inDegree[input[2]]++;
        }
        else
        {
            adj[input[2]].push_back(input[0]);
            inDegree[input[0]]++;
        }
    }

    unordered_map<char, bool> visited;
    for (auto [ch, vec] : adj)
    {
        visited[ch] = false;
    }

    int cnt = 0;
    vector<char> cur;
    allTopologicalSort(cur, &cnt, visited, inDegree, adj);
    return to_string(cnt);
}

int main()
{
    int n;
    cin >> n;
    vector<string> inputs(n);
    for (int i = 0; i < n; i++)
    {
        cin >> inputs[i];
    }
    cout << LineOrdering(inputs) << endl;
    return 0;
}