#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>#include <climits>#include <string>#include <iostream>#include <map>#include <cstdlib>#include <list>#include <stack>using namespace std;typedef long long LL;const int maxn = 205;int n,val[maxn][maxn];bool e[maxn][maxn];char buf[1024];int getval(char *s) {    int len = strlen(s),ret = 0;    for(int i = 0;i < len;i++) {        ret |= (1 << (s[i] - ‘a‘));    }    return ret;}void floyd() {    for(int i = 1;i <= n;i++) {        for(int j = 1;j <= n;j++) {            for(int k = 1;k <= n;k++) {                val[j][k] |= val[j][i] & val[i][k];            }        }    }}int main() {    while(scanf("%d",&n),n) {        memset(val,0,sizeof(val));        int a,b;        while(scanf("%d%d",&a,&b),a) {            scanf("%s",buf);            val[a][b] = getval(buf) ;        }        floyd();        while(scanf("%d%d",&a,&b),a) {            int cnt = 0;            for(int i = 0;i < 26;i++) {                if(val[a][b] & (1 << i)) {                    cnt++;                    putchar(i + ‘a‘);                }            }            if(cnt == 0) putchar(‘-‘);            puts("");        }        puts("");    }    return 0;}