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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. int main() {
  5. 	int n;
  6. 	cin>>n;
  7. 	int k=0;
  8.             int f=1;
  9.             for(int i=1;i<=n;i++)
  10.             f=f*i;
  11.             for(int i=1;i<=n;i++)
  12.             {
  13.                 int c=1,r=1;
  14.                 for(int j=1;j<=i;j++)
  15.                 r=r*j;
  16.                 for(int j=1;j<=(n-i);j++)
  17.                 c=c*j;
  18.  
  19.                 k=k+(f/(c*r));
  20.             }
  21.             k=k-(n-1);
  22.             cout<<k;
  23. 	// your code goes here
  24. 	return 0;
  25. }
Success #stdin #stdout 0s 5676KB
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1
https://ideone.com/lmddDx
language:
C++ (gcc 8.3)
created:
2 years ago
visibility:
public

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