/*
 USER: pdp23u8
 NAME: Loukas Xanthos
 LANG: C++
 TASK: company
 COMMENTS: pdp23 part 2 (High School)
*/

#include <iostream>
#include <fstream>
#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, uint females, uint males)
{

    if(sex[node] == F) {
        diff += males;
        females++;
    }
    else if(sex[node] == M) {
        diff -= females;
        males++;
    }

    for(register uint i = 0; i < (uint) graph[node].size(); i++) {
        DFS(graph[node][i], females, males);
    }
}

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

    fin >> N;
    for(register 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(boss, 0, 0);

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