（学生成绩）
n = int(input())
stu = []
for i in range(n): inp = list(input().split()) stu.append(dict(num=inp[0],name=inp[1],merit=inp[2]))
m = input().strip()
t = True
for i in range(n): if stu[i]['num'] == m: print(stu[i]['num'],stu[i]['name'],stu[i]['merit']) t = False
if t: print('Not Found!')
（对称矩阵）
n = int(input())
a = [[0 for j in range(n)] for i in range(n)]
for i in range(n): for j in range(n): a[i][j] = str(abs(j-i))
for i in range(n): print(' '.join(a[i]))
（两军交锋）
t = int(input())
for i in range(t): u,v,w,l = list(map(float,input().split())) print('%.3f'%((l*w)/(u+v)))
（砍树）
m, n = list(map(int, input().split()))
a = [i+1 for i in range(m)]
b = []
i = 0
while True: if a[i % m] in b: break else: b.append(a[i % m]) i += (n+1)
print(len(b))