codeforces_630F.Selection of Personnel

One company of IT City decided to create a group of innovative developments consisting from 5 to 7 people and hire new employees for it. After placing an advertisment the company received n resumes. Now the HR department has to evaluate each possible group composition and select one of them. Your task is to count the number of variants of group composition to evaluate.

Input

The only line of the input contains one integer n (7 ≤ n ≤ 777) — the number of potential employees that sent resumes.

Output

Output one integer — the number of different variants of group composition.

Examples

Input

1

7

Output

C++

1

29

一样要考虑溢出问题

#include <iostream>#include <cstdio>#include <cstdlib>#include <cmath>using namespace std;long long solve(int n,int m){    int num=1;    long long ans=1;    while(m--)    {        ans*=(n-m);        ans/=num;        num++;    }    return ans;}int main(){    int n,i;    scanf("%d",&n);    long long ans=0;    for(i=5;i<=7;i++)    {        ans+=solve(n,i);    }    printf("%lld\n",ans);    return 0;}