​

m = int(input())

if 20<=m and m<=100:
    for i in range(11,m):
        m += i

    print("sum = "+str(m))

else:
    print("error")


================================================================


x = float(input())
if x == 0:
    y = x
else:
    y = 1/x
print("f({:.1f}) = {:.1f}".format(x,y))


================================================================


a, n = input().split()
plus = 0
n = int(n)
for n in range(1, n+1):
    an = int(n * a)
    n += 1
    plus += an
print("s = {}".format(plus))

================================================================


N = int(input())
plus = 0

for i in range(1, N*2, 2):
    P = 1/i
    plus += P
    i += 1
print("sum = {:.6f}".format(plus))

================================================================



N = int(input())
plus = 0

for i in range(1, N+1, 2):
    P = i/(2*i-1)
    plus += P
    i += 1
for i in range(2, N+1, 2):
    Q = i/(2*i - 1)
    plus -= Q
    i += 1
print("{:.3f}".format(plus))

================================================================


A, B = input().split(",")   # 以逗号作为两个参数的分隔符
B = int(B.strip(' '))       # 将A、B前后的空格符去掉
A = A.strip(' ')
AB = B * A

print(int(AB))

================================================================


A, B = input().split(",")   # 逗号分隔数值和进制
B = int(B)                  # 转换公式：int('A',B)
print(int(A, B))            # 所以B需是整型，A需是字符串

↓

2进制

8进制

10进制

16进制

2进制

-

bin(int(x, 8))

bin(int(x, 10))

bin(int(x, 16))

8进制

oct(int(x, 2))

-

oct(int(x, 10))

oct(int(x, 16))

10进制

int(x, 2)

int(x, 8)

-

int(x, 16)

16进制

hex(int(x, 2))

hex(int(x, 8))

hex(int(x, 10))

-

================================================================


# 数学思路
A, B, C = input().split(" ")
A, B, C = int(A), int(B), int(C)
a = max(A, B, C)
c = min(A, B, C)
b = A + B + C - a - c
a, b, c = str(a), str(b), str(c)
d = '->'
all = d.join((c, b, a))
print(all)


# 转换成整型放入列表排序后取出
# 本以为不用转整型，列表有内建的排序方式
# 但如果有负数，排序就与正常的不一致
# 所以仍需要先转为整型再转回字符串进行拼接
A, B, C = input().split(" ")
A, B, C = int(A), int(B), int(C)
R = sorted([A, B, C])
R[0], R[1], R[2] = str(R[0]), str(R[1]), str(R[2])
print("->".join((R[0], R[1], R[2])))


================================================================


lower, upper = input().split(" ")

if int(lower) <= int(upper) <= 100:
    print("fahr celsius")
    for i in range(int(lower), int(upper) + 1, 2):
        C = 5 * (i - 32) / 9
        print("{}".format(i) + "{:>{}.1f}".format(C, 6))
else:
    print("Invalid.")

================================================================


m, n = input().split()
m = int(m)
n = int(n)
sum = 0

for m in range(m, n+1):
    S = pow(m, 2) + pow(m, -1)
    sum += S
print("sum = {:.6f}".format(sum))

================================================================


a, b, c = input().split()
a = int(a)
b = int(b)
c = int(c)
s = (a + b + c)/2
area = pow(s*(s-a)*(s-b)*(s-c), 1/2)
L = a + b + c
if (a+b) > c and (a+c) > b and (b+c) > a:
    print("area = {:.2f}; perimeter = {:.2f}".format(area, L))
else:
    print("These sides do not correspond to a valid triangle")

================================================================


A, B = input().split()
A, B = int(A), int(B)
Sum = 0
i = 0
for A in range(A, B+1):
    i += 1
    if i % 5 == 0 or A == B:
        print("{:>5d}".format(A))

    else:
        print("{:>5d}".format(A), end='')

    Sum += A
print("Sum = {}".format(Sum))