import sys
import heapq

def main():
    input = sys.stdin.read
    data = input().split()
    idx = 0
    N = int(data[idx])
    idx += 1
    M = int(data[idx])
    idx += 1

    adj = [[] for _ in range(N+1)]  # 1-based

    for _ in range(M):
        k_i = int(data[idx])
        idx += 1
        c_i = int(data[idx])
        idx += 1
        s = list(map(int, data[idx:idx + k_i]))
        idx += k_i

        # Add all pairs
        for x in range(k_i):
            for y in range(x+1, k_i):
                a = s[x]
                b = s[y]
                w = (a + b + 1) // 2 + c_i
                adj[a].append((b, w))
                adj[b].append((a, w))

    # Dijkstra's algorithm
    INF = float('inf')
    dist = [INF] * (N + 1)
    dist[1] = 0
    heap = []
    heapq.heappush(heap, (0, 1))

    while heap:
        current_dist, u = heapq.heappop(heap)
        if current_dist > dist[u]:
            continue
        if u == N:
            print(current_dist)
            return
        for v, w in adj[u]:
            if dist[v] > dist[u] + w:
                dist[v] = dist[u] + w
                heapq.heappush(heap, (dist[v], v))

    print(-1)

if __name__ == '__main__':
    main()