#include <bits/stdc++.h>

using namespace std;

const int mod = 998244353, N = 2005;
int f[N][N], g[N][N];
int a[N], x[N], b[N], y[N];
char s[N];
bool isCap(char c)
{
	return 'A' <= c && c <= 'Z';
}
void read()
{
	int p = 0;
	char c = '\0';
	while(!isCap(c = getchar()));
	while(c >= 32)
	{
		s[p++] = c;
		c = getchar();
	}
	s[p] = '\0';
}
void dfs(int u, int v)
{
	if(f[u][v] == -2)
	{
		printf("-1\n");
		exit(0);
		return ;
	}
	int w;
	if(f[u][v] != -1)
		return ;
	f[u][v] = -2;
	if(v == a[u])
	{
		f[u][v] = x[u];
		g[u][v] = 1;
		return ;
	}
	g[u][v] = 1;
	dfs(y[u], b[u]);
	g[u][v] = (g[u][v] + g[y[u]][b[u]]) % mod;
	w = f[y[u]][b[u]];
	dfs(w, v);
	g[u][v] = (g[u][v] + g[w][v]) % mod;
	f[u][v] = f[w][v];
}

int main()
{
	int n, i;
	memset(f, -1, sizeof(f));
	scanf("%d", &n);
	for(i = 1; i <= n; i++)
	{
		read();
		if(s[0] == 'H')
			sscanf(s, "HALT; PUSH %d GOTO %d", b + i, y + i);
		else
			sscanf(s, "POP %d GOTO %d; PUSH %d GOTO %d", a + i, x + i, b + i, y + i);
		// printf("!!%d %d %d %d\n", a[i], x[i], b[i], y[i]);
	}
	dfs(1, 0);
	printf("%d\n", g[1][0]);
	return 0;
}