1)
n = int(input())
a = n // 100
b = (n // 10) % 10
c = n % 10
print(a + b + c)

2)
n = int(input())
if n % 4 == 0 and n % 100 != 0 or n % 400 == 0:
    print('YES')
else:
    print('NO')

3)
a = input()
b = input()
c = input()
a = float(a)
b = float(b)
c = float(c)
dis = b**2 - 4*a*c
print('Dis = ' + str(dis))
if dis < 0:
    print('Нет корней')
elif dis == 0:
    x = -b / (2 * a)
    print('x = ' + str(x))
else:
    x1 = (-b + discriminant ** 0.5) / (2 * a)
    x2 = (-b - discriminant ** 0.5) / (2 * a)
    print('x₁ = ' + str(x1))
    print('x₂ = ' + str(x2))

4)
n = int(input())
if (1 <= n <= 2) or (n == 12):
    print('Зимний период')
elif 3 <= n <= 5:
    print('Весенний период')
elif 6 <= n <= 8:
    print('Летний период')
elif 9 <= n <= 11:
    print('Осенний период')
else:
    print('Не является временем года')

5)
a = int(input())
b = int(input())
c = int(input())
if (a == b) or (b == c) or (c == a):
    print('Yes')
else:
    print('No')

6)
n = int(input(''))
if 1000 <= n <= 10000:
    n1 = n // 1000
    n2 = n // 100 % 10
    n3 = n % 100 // 10
    n4 = n % 10
    if (n1 > n2) and (n2 > n3) and (n3 > n4):
        print('Yes')
    else:
        print('No')

7)
n = int(input(''))
if 1000 <= n <= 9999:
n1 = n // 1000
n2 = (n // 100) % 10
n3 = (n % 100) // 10
n4 = n % 10
if (n1 == n4) and (n2 == n3):
    print('yes')
else:
    print('No')

8)
a = int(input('день'))
b = int(input('месяц'))
c = int(input('Год'))
if (1 <= a <= 31) and (1 <= b <= 7) and (b % 2 != 0) and (c > 0):
    print('yes')
elif (1 <= a <= 31) and (8 <= b <= 12) and (b % 2 == 0) and (c > 0):
    print('yes')
elif (1 <= a <= 28) and (b == 2) and (c > 0):
    print('yes')
else:
    print('no')

9)
a = int(input("a = "))
b = int(input("b = "))
c = int(input("c = "))
if a + b > c and a + c > b and b + c > a:
    print("существует")
else:
    print("не существует")

10)
a = int(input('Число 1'))
b = int(input('Число 2'))
c = int(input('Число 3'))
n1 = a + b
n2 = a + c
n3 = b + c
if n1 > n2 and n1 > n3:
    print(a, b)
elif n2 > n1 and n2 > n3:
    print(a, c)
else:
    print(b, c)