#include <stdio.h>#include <string.h>int f[505], mp[505][505];int main(){ int t, n, m, a, b, s; double ans; scanf("%d", &t); while(t--) { scanf("%d%d", &n, &m); s = 0; for(int i = 1; i <= m; i++) { scanf("%d", &f[i]); } memset(mp, 0, sizeof(mp)); for(int i = 1; i <= m; i++) { scanf("%d", &a); b = f[i]; if(mp[a][b] == 0) { mp[a][b] = 1; mp[b][a] = 1; s++; } } ans = s * 1.0 / n; printf("%.3lfn", ans); } return 0;}
