Problem:
Score : 100 points

Problem Statement

Given an integer N not less than 3, find the sum of the interior angles of a regular polygon with N sides.

Print the answer in degrees, but do not print units.

Constraints

3 \leq N \leq 100

Input

Input is given from Standard Input in the following format:

N

Output

Print an integer representing the sum of the interior angles of a regular polygon with N sides.

Sample Input 1

3

Sample Output 1

180

The sum of the interior angles of a regular triangle is 180 degrees.

Sample Input 2

100

Sample Output 2

17640

Solution in C (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
int compare_int(const void *a, const void *b)
{
//    return *(int*)a - *(int*)b;
    return *(long long*)a - *(long long*)b;
}
//  qsort(A, b, sizeof(int), compare_int);

int main()
{
  int a ,b, c, d, e, X, Y;
//  long long  b, c, d, e, X, Y;
  //  double  c;
  long long  A[200003]={};
  int  B[100003]={};
  int  C[100003][11]={};

  int  flag[1003]={};

//  long long  a, b, c, d, X, Y;
  char s[101][101]={};
//  int N, M;
//  int A[1000000001]={};
//  long long  C[101]={};
  int i,j,k;
//  int flag=0;
//  int tmp=0;
  char tmp[101]={};
//  int min=1000000;
  long long min=100000001;
  int len=0;
  int l=0;
  int r=1000001;
  int cnt=0;
  int num=0;
  int ans=0;
  int max=0;
  int addr=0;
  int ptn=0;
//  bool on_off[100]={};
  
//  char alp[26]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};

  //  a=0;
//  scanf("%lld %lld", &a, &b);
//  scanf("%d%d", &a,&c);
//  cnt = strlen(t);
// printf("%d\n",a);
  scanf("%d", &a);
  printf("%d\n", 180*(a-2));

    
    
    
    
    
//    printf("%s %d %d\n", s[i],C[i][0],C[i][1]);
   // printf("%d\n", C[i][1]);
/*  for(i=0;i<addr;i++){
//  scanf("%lld%lld", &B[0][i],&B[1][i]);
//    ans=ans+A[i];
    printf("%lld ", A[i]);
  }
*/
//    printf("%d ", cnt);
   
//  ans=a*3;
//  ans=(ans+b)/2;
//  printf("%d\n", ans);

  
//  printf("%lf\n",ans);
  //  //  if(flag==0)   printf("TLE\n");
//    if(max < cnt - max)  printf("Yes\n");
//    else  printf("No\n");
  
return 0;
}