#include<iostream>
#include<cstring>
#include<vector>
using namespace std;
using LL = long long;

struct Node{
    int a, b, c, d;
};

int stk[(1 << 23) + 10], top;

int main(){

#ifdef LOCAL
    freopen("data.in", "r", stdin);
    freopen("data.out", "w", stdout);
#endif

    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(0);

    int n;
    cin >> n;
    vector<Node> p(n + 1);
    for(int i = 1; i <= n; i++){
        string s;
        cin >> s;
        if (s[0] == 'H'){
            string _; int v1, v2;
            cin >> _ >> v1 >> _ >> v2;
            p[i] = {0, 0, v1, v2}; 
        }
        else{
            string _; int v1, v2, v3, v4;
            cin >> v1 >> _ >> v2 >> _ >> _ >> v3 >> _ >> v4;
            p[i] = {v1, v2, v3, v4};
        }
    }
    int cur = 1;

    for(int i = 1; ; i++){
        if (i > (1 << 23)){
            cout << -1 << '\n';
            return 0;
        }
        if (top == 0 and p[cur].a == 0){
            cout << i << '\n';
            return 0;
        }
        if (top > 0 and stk[top] == p[cur].a){
            top--;
            cur = p[cur].b;
        }
        else{
            stk[++top] = p[cur].c;
            cur = p[cur].d;
        }
    }

}