import heapq

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

    adj = [[] for _ in range(N + M + 2)]  # Virtual nodes are N+1 to N+M

    for i in range(M):
        k = int(data[ptr])
        c = int(data[ptr + 1])
        s = list(map(int, data[ptr + 2:ptr + 2 + k]))
        ptr += 2 + k

        virtual_node = N + 1 + i  # i starts from 0, virtual nodes start at N+1

        for u in s:
            cost = (u + c + 1) // 2
            adj[u].append((virtual_node, cost))
            adj[virtual_node].append((u, cost))

    # Dijkstra's algorithm
    INF = float('inf')
    dist = [INF] * (N + M + 2)
    dist[1] = 0
    heap = []
    heapq.heappush(heap, (0, 1))

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

    print(dist[N] if dist[N] != INF else -1)

if __name__ == '__main__':
    main()