main.py

from collections import deque
import sys


def solve(data: str) -> str:
    tokens = list(map(int, data.split()))
    if not tokens:
        return ""
    it = iter(tokens)
    n = next(it)
    m = next(it)
    start = next(it)
    graph = [[] for _ in range(n + 1)]
    for _ in range(m):
        u = next(it)
        v = next(it)
        graph[u].append(v)
        graph[v].append(u)
    days = [-1] * (n + 1)
    days[start] = 0
    queue = deque([start])
    while queue:
        node = queue.popleft()
        for nxt in graph[node]:
            if days[nxt] != -1:
                continue
            days[nxt] = days[node] + 1
            queue.append(nxt)
    reach = days[1:]
    total_days = max(reach)
    unreached = sum(1 for value in reach if value == -1)
    return "\n".join(
        [
            f"total_days={total_days}",
            "days=" + " ".join(map(str, reach)),
            f"unreached={unreached}",
        ]
    )


if __name__ == "__main__":
    sys.stdout.write(solve(sys.stdin.read()).strip())
    sys.stdout.write("\n")