Problem:
Score : 100 points

Problem Statement

Given is an integer r.

How many times is the area of a circle of radius r larger than the area of a circle of radius 1?

It can be proved that the answer is always an integer under the constraints given.

Constraints

1 \leq r \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

r

Output

Print the area of a circle of radius r, divided by the area of a circle of radius 1, as an integer.

Sample Input 1

2

Sample Output 1

4

The area of a circle of radius 2 is 4 times larger than the area of a circle of radius 1.

Note that output must be an integer - for example, 4.0 will not be accepted.

Sample Input 2

100

Sample Output 2

10000

Solution in C (Clang 3.8.0) (judge verdict: Accepted)

//Twitter@KonoLv1 2020年春からエンジニア見習いデビュー！
 
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
 
int main(void){
    int i,j;            //  ループ文に使用
    int x,y,z; 
    int count1,count2,count;   //  カウント用に使用
    int flg,mode;
    i = j = x = y = z = count1 = count2 = count = flg = mode = 0;
    int n;
    double dx,dy;
    int box[1024] = {};
    int box2[1024] = {};
    char s[200001] = {};        //  文字列
    char s2[200001] = {};        //  文字列

 
    //  入力処理
    
    // scanf("%s",s); // 文字列
     scanf("%lf",&dy); // 整数
    // scanf("%lf",dx); // 小数
    
    /*
    for (i = 0; i < n; i++){
        scanf("%d"  
    }
    */
    //  計算処理
    dx = 1;
    dx = dx * dx * 3.14;
    dy = dy * dy * 3.14;
    //  出力処理
 

    printf("%.0f",dy / dx);
}



    /* 資材置き場 */
    /*
    「dx」に入っているDouble型の数値の下1桁（それ以下四捨五入）表示
     printf("%.1f",dx);
    
    
    文字列[s]に入っている文字に「a」が含まれる場合、全て「b」に変更する
    while(1){
        if (s[i] == '\0'){
            break;
        }
        
        if (s[i] == 'a'){
            s[i] = 'b';
        }
        i++;
    }
    
    
    */