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June 10, 2019 20:12
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| N, M = map(int, input().split()) | |
| a = {int(input()) for i in range(M)} | |
| n, m = 1, 0 | |
| for i in range(1, N + 1): | |
| n, m = (i not in a) * (n + m) % 1000000007, n | |
| print(n) |
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