#include <iostream>
#include <fstream>
#include <stack>
#include <vector>
using namespace std;

#define MAX_N 400002
#define F false
#define M true

typedef unsigned long int uint;
uint N, boss;
long int diff;
vector<uint> graph[MAX_N];
vector<bool> sex(MAX_N);

void DFS()
{
    uint node = boss;
    uint females = 0, males = 0;
    stack<uint> s;
    s.push(boss);
    while(!s.empty())
    {
        node = s.top(); s.pop();
        if(sex[node] == F){
            diff += males;
            females++;
        }
        else {
            diff -= females;
            males++;
        }
        for(uint i = 0; i < graph[node].size(); i++) {
            s.push(graph[node][i]);
        }
        s.pop();
        if(sex[node] == F) females--;
        else males--;
    }
}

int main()
{
    ifstream fin("company.in");
    ofstream fout("company.out");

    fin >> N;

    for(uint i = 1; i <= N; i++)
    {
        uint sup;
        char tmps;

        fin >> sup;
        fin >> tmps;

        if(tmps == 'f')
            sex[i] = F;
        else
            sex[i] = M;
        if(sup == 0)
            boss = i;
        else
            graph[sup].push_back(i);
    }

    DFS();

    fout << diff << '\n';
    fin.close();
    fout.close();
    return 0;
}