#include <bits/stdc++.h>
using namespace std;
int n,e,k,a[11][11],ans;
bool vis[11];
void dfs(int x);
int main(){
	scanf("%d%d",&n,&e);
	for(int i = 1;i<=e;i++){
		int c,b;
		scanf("%d%d",&c,&b);
		a[c][b] = 1;
		a[b][c] = 1;
	}
	scanf("%d",&k);
	vis[3] = true;
	dfs(3);
	printf("%d",ans);
	return 0;
}
void dfs(int x){
	if(x == k){
		ans++;
		return;
	}
	for(int i = 1;i<=n;i++)
		if(a[x][i] == 1 && vis[i] == false){
			vis[i] = true;
			dfs(i);
			vis[i] = false;
		}
}