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#include <bits/stdc++.h>

using namespace std;

const int N = 1e6 + 7;
const int MX = 1e9 + 7;

int n, m, a, b;
vector <int> G[N];

bool vis[N];
bool reached[N];

int nr[N];
vector <int> reachable;
vector <int> canReach[N];

void dfs(int u){
	vis[u] = true;
	for(auto v: G[u])
		if(!vis[v])
			dfs(v);
}

int calc(){
	int ret = 0;
	int _n = reachable.size();

	for(int i = 1; i < (1 << _n); ++i){
		auto is = [&](int v) -> bool{
			return (i & (1 << v)) > 0;
		};
		
		bool ok = true;
		for(int j = 1; j <= a; ++j){
			bool good = false;
			for(auto u: canReach[j])
				if(is(nr[u])){
					good = true;
					break;
				}
			
			if(!good){
				ok = false;
				break;
			}
		}
		
		ret += ok;
	}
	
	return ret;
}

int main(){
	scanf("%d %d %d %d", &n, &m, &a, &b);
	for(int i = 1; i <= m; ++i){
		int u, v;
		char s[5];
		scanf("%d %s %d", &u, s, &v);
		
		G[u].push_back(v);
		if(s[1] == '-')
			G[v].push_back(u);
	}
	
	for(int i = 1; i <= a; ++i){
		for(int j = 1; j <= n; ++j)
			vis[j] = false;

		dfs(i);
		for(int j = a + 1; j <= a + b; ++j)
			if(vis[j]){
				canReach[i].push_back(j);
				reached[j] = true;
			}
	}
	
	for(int i = a + 1; i <= a + b; ++i)
		if(reached[i]){
			nr[i] = reachable.size();
			reachable.push_back(i);
		}
	
	int ans = calc();
	for(int i = a + 1; i <= a + b; ++i)
		if(!reached[i])
			ans = (ans + ans) % MX;
	
	printf("%d\n", ans);
	return 0;
}