# 周長

print(int(int(input())*2*3.14))

# 浮點數位數

print(len(input().split('.')[1]))

# 格式化輸出

n = input()
print(f'My name is {n}, it is {len(n)} characters.')

# 文字開頭、中間、結尾

while True:
    try:
        n = input()
        if len(n)%2:
            print(f'{n[0].lower()},{n[len(n)//2].lower()},{n[-1].lower()}')
        else:
            print(f'{n[0].lower()},{n[(len(n)-1)//2].lower()+n[(len(n))//2].lower()},{n[-1].lower()}')
    except:
        break

# 隱私文字

n = input().split()
for i in range(len(n)):
    if 1 < i < len(n)-2:
        print('*'*(len(n[i])),end=' ')
    else:
        print(n[i],end=' ')

# 保持順序移動0

n = input().split(',')
ans = ','.join([i for i in n if i!='0']) + ','
ans += ','.join([i for i in n if i=='0'])
print(ans)

# 最常出現單字

d = {}
s = input().lower().split()
for i in s:
    if i not in d:
        d[i] = 1
    else:
        d[i] += 1
l = [i for i in d if d[i] == max(d.values())]
if len(l) != 1:
    print('No')
else:
    print(l[0], d[l[0]])

# 兩索引相加等於目標

while True:
    try:
        s, t = input().split()
        t = int(t)
        s = [int(i) for i in s.split(",")]
        flag = False
        for i in range(len(s)):
            for j in range(i+1, len(s)):
                if s[i]+s[j] == t:
                    print(f"{i},{j}")
                    flag = True
                    break
            if flag:
                break
    except:
        break

# 在索引中插入值並保持順序

import bisect
s, t = input().split()
t = int(t)
s = [int(i) for i in s.split(",")]
print(bisect.bisect_left(s, t))

# 序列中的美好組合總數

while True:
    try:
        s = [int(i) for i in input().split(",")]
        t = 0
        for i in range(len(s)):
            for j in range(i+1, len(s)):
                if s[i]==s[j]:
                    t += 1
        print(t)
    except:
        break