820

#### # for i in range(19):# #     a = list(map(int, input().split()))# #     n = int(input())# #     for k in range(n):# #         x, y = map(int, input().split())# #         for i in range(19):# #             a[i] = (int(a[i])-1)*-1# #             for j in range(19):# #                 a[j] = (int(a[j])-1)*-1# #             for i in range(19):# #                 for j in range(19):# #                      print(a[i][j], end=' ')# #                  print()# # a=[]# # for i in range(10) :# #     b=list(map(int,input().split()))# #     a.append(b)# ## # r=1     # row 행# # c=1     # column 열# # while True :# #     a[r][c]=9# #     if a[r][c+1] != 1 :     # 오른쪽으로 갈 수 있다면# #         c+=1# #     elif a[r+1][c] !=1 :# #         r+=1# #     else :# #         break# ## #     if(a[r][c]==2) :# #         a[r][c] = 9# #         break# # for i in range(10) :# #     for j in range(10) :# #         print(a[i][j],end=' ')# #     print()## # a=[]# # for i in range(19) :# #     b=list(map(int,input().split()))# #     a.append(b)# # n = int(input())## '''# 반환자료형 x void, int, float 구분없음## '''## # def f() :# #     global x        # 함수 밖에서 선언된 변수 쓸때# #     print("hello"*x)# ## # x = int(input())# # f()### # def mysum(a, b) :# #     return a+b# # x, y = map(int, input().split())# # print(mysum(x,y))## # def f(a):# #     if(a%2==0) :# #         print('even')# #     else :# #         print('odd')# # a=int(input())# # f(a)# # def f(a) :# #     b=0# #     for i in range(2,a) :# #         if(a%i==0):# #             print('composite')# #             b=b+1# #             break# #     if(b==0) :# #         print('prime')# # a=int(input())# # f(a)# # def f(a) :# #     b=0# #     for i in range(1,a+1) :# #         if(a%i==0) :# #             b=b+1# #     return b# ## # a=int(input())# # print(f(a))# def f(a,b,c):#     for i in range(1,a+1) :#         if(b[i]>=c) :#             print(i+1)#             break;# a=int(input())# b=list(map(int,input().split()))# c=int(input())# f(a,b,c)def f(a):    a=a*a    a=a*3.14    print(format(a,".2f"))a=int(input())f(a)