/*
LANG: C
TASK: company
*/
#include <stdio.h>
#include <stdlib.h>

#define MAX 400000

int N, head[MAX], r_m[MAX], r_f[MAX];
char sex[MAX];

int main() {
    FILE *file;
    int i, j, D;

    file = fopen("company.in", "r");
    fscanf(file, "%d\n", &N);
    for (i=0; i<N; ++i)
        fscanf(file, "%d %c\n", &head[i], &sex[i]);
    fclose(file);

    D=0;
    for (i=0; i<N; ++i) {
        r_m[i]=0;
        r_f[i]=0;
        for (j=head[i]-1; j>=0; j=head[j]-1) {
            (sex[j] == 'm')? ++r_m[i] : ++r_f[i];
            if (j<i) {
                r_m[i] += r_m[j];
                r_f[i] += r_f[j];
                break;
            }
        }
        if (sex[i] == 'm')
            D -= r_f[i];
        else
            D += r_m[i];
    }

    file = fopen("company.out", "w");
    fprintf(file, "%d\n", D);
    fclose(file);

    return 0;
}