import sys
import heapq

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

    adj = [[] for _ in range(N + 1)]
    for _ in range(M):
        k_i = int(input[ptr])
        ptr += 1
        c_i = int(input[ptr])
        ptr += 1
        s_i = list(map(int, input[ptr:ptr + k_i]))
        ptr += k_i
        s_1 = s_i[0]
        for u in s_i[1:]:
            w = (u + s_1 + 1) // 2 + c_i
            adj[u].append((s_1, w))
            adj[s_1].append((u, w))

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

    while heap:
        dist_u, u = heapq.heappop(heap)
        if dist_u > d[u]:
            continue
        for v, w in adj[u]:
            if d[v] > d[u] + w:
                d[v] = d[u] + w
                heapq.heappush(heap, (d[v], v))

    if d[N] == INF:
        print(-1)
    else:
        print(d[N])

if __name__ == "__main__":
    main()