17 lines
200 B
C++
17 lines
200 B
C++
#include<cstdio>
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using namespace std;
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long long f(int n)
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{
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if(n==1) return 0;
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if(n==2) return 1;
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return f(n-2)+f(n-1);
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}
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int main()
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{
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int n;
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scanf("%d",&n);
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printf("%lld\n",f(n));
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return 0;
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}
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