#include<bits/stdc++.h>
using namespace std;
using ll =long long;
#define int long long
int fa[2010];
int siz[2010];
const ll M=998244353;
void solve(){
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)   {fa[i]=0;siz[i]=0;}
    vector<string> s(n+1);
    vector<bool> ex(n+1);
    for(int i=0;i<=n;i++)  getline(cin, s[i]);
    vector<array<int,4>> mp(n+1);
    auto getf=[&](string & s,int pz)->pair<int,int> {
        int ans=0;
        while(pz<(int)s.size()){
            if(s[pz]<='9'&&s[pz]>='0')  ans=ans*10+s[pz++]-'0';
            else break;
        }
        return {ans,pz};
    };
    for(int i=1;i<=n;i++){
        if(s[i].substr(0,4)=="HALT"){
            pair<int,int> w1=getf(s[i],11);
            pair<int,int> w2=getf(s[i],w1.second+6);
            mp[i]={-1,-1,w1.first,w2.first};
        }
        else{
            pair<int,int> w1=getf(s[i],4);
            pair<int,int> w2=getf(s[i],w1.second+6);
            pair<int,int> w3=getf(s[i],w2.second+7);
            pair<int,int> w4=getf(s[i],w3.second+6);
            mp[i]={w1.first,w2.first,w3.first,w4.first};
        }
    }
    vector<array<int,3>> stk;//num,ope,pz
    int pz=1;
    vector<bool> flag(n+1);
    int pre=-1;
    ll ans=1;int tot=0;
    while (1){
        tot++;
        // cerr<<"???"<<tot++<<'\n';
        // cerr<<"___\n";
        // cerr<<pz<<'\n';
        // for(auto [x,y,z]:stk){
        //     cerr<<x<<' '<<y<<' '<<z<<'\n';
        // }
        // for(int j=1;j<=n;j++){
        //     cerr<<fa[j]<<' ';
        // }
        // cerr<<"___\n";
        // cerr<<'\n';
        if(flag[pz])    {cout<<"-1\n";return ;}
        if(stk.empty()&&mp[pz][0]==-1){
            cout<<(ans%M+M)%M<<'\n';
            return ;
        }
        if(!stk.empty()&&stk.back()[0]==mp[pz][0]){
            ans=(ans+1)%M;
            if(mp[pz][1]==stk.back()[2]){
                cout<<"-1\n";return ;
            }
            if(fa[stk.back()[2]]==0){
                fa[stk.back()[2]]=mp[pz][1];
                siz[stk.back()[2]]=(ans-mp[pz][1])%M;        
            }
            flag[stk.back()[2]]=0;
            stk.pop_back();
            pz=mp[pz][1];
            continue;
        }
        int pre=pz;
        while(fa[pz]){
            ans=(ans+siz[pz])%M;
            pz=fa[pz];
            if(pz==pre){
                cout<<"-1\n";
                return ;
            }
            if(flag[pz])    {cout<<"-1\n";return ;}
            if(stk.empty()&&mp[pz][0]==-1){
                cout<<(ans%M+M)%M<<'\n';
                return ;
            }
            if(!stk.empty()&&stk.back()[2]==mp[pz][0]){
                ans=(ans+1)%M;
                if(fa[stk.back()[2]]==0){
                    fa[stk.back()[2]]=mp[pz][1];
                    siz[stk.back()[2]]=ans-mp[pz][1];        
                    if(fa[stk.back()[2]]==stk.back()[2]){
                        cout<<"-1\n";return ;
                    }
                }
                pz=mp[pz][3];
                stk.pop_back();
                continue;
            }
            else continue;
        }
        ans=(ans+1)%M;
        stk.push_back({mp[pz][2],ans,pz});
        flag[pz]=1;
        pz=mp[pz][3];
    }
    
}
signed main(){
    ios::sync_with_stdio(0),cin.tie(0);
    int _ =1;
    // cin>>_;
    while(_--) solve();
}