17 lines
338 B
Python
17 lines
338 B
Python
N = int(input())
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link = [[] for _ in range(N+1)]
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visited = [False] * (N+1)
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for _ in range(int(input())):
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a, b = map(int, input().split())
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link[a].append(b)
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link[b].append(a)
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def dfs(now) :
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visited[now] = True
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for nt in link[now] :
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if not visited[nt] :
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dfs(nt)
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dfs(1)
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print(visited.count(True)-1) |