18 lines
350 B
C++
18 lines
350 B
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 1010;
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int a[N];
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int n, cnt;
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int main() {
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cin >> n;
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for (int i = 1; i <= n; i++)
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for (int j = 1; j <= 2 * n; j++)
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if (j % i == 0)a[j] = !a[j];
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for (int i = 1; i <= 2 * n; ++i)
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if (a[i]) cnt++;
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printf("%d", cnt);
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return 0;
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} |