#include<bits/stdc++.h>
using namespace std;
struct node{
	int step;
	string s;
	node(int step1,string s1){
		step=step1;
		s=s1;
	}
};
string s[25][10],a,b;
int z=0;
map<string,bool> m;
void bfs(string a,string b){
	queue<node> q;
	q.push(node(0,a));
	while (!q.empty()){
		node now=q.front();
		q.pop();
		if (now.s==b){
			cout<<now.step;
			exit(0);
		}
		for (int i=0;i<z;i++){
			string qaq=now.s;
			while (114514){
				//cout<<qaq.find(s[i][0]);
				if (qaq.find(s[i][0])<10000) {
					qaq.replace(qaq.find(s[i][0]),(int)s[i][0].size(),s[i][1]);
					if (now.step<10 && !m[qaq]) q.push(node(now.step+1,qaq));
					qaq[qaq.find(s[i][0])]='%';
					m[qaq]=1;
				}else{
					break;
				}
			}
		}
		
	}
	cout<<"NO ANSWER!";
	exit(0);
}
int main()
{
	cin>>a>>b;
	while (cin>>s[z][0]>>s[z][1]) {
		z++;
	}
	bfs(a,b);
}