题目：


思路：
1注意多项式非零项的数目
2两项相加为0时不输出
3 测试点1未通过
代码：

C={}
A=list(input().split())
B=list(input().split())

count=0
for i in range(int(A[0])):
        C[A[i*2+1]]=float(A[i*2+2])
        count = count + 1

for i in range(int(B[0])):
    if B[i*2+1] not in C:
        C[B[i * 2 + 1]] = float(B[i * 2 + 2])
        count = count + 1
    else:
        C[B[i * 2 + 1]]= C[B[i * 2 + 1]]+float(B[i * 2 + 2])
        if(C[B[i * 2 + 1]]==0):
            count = count - 1

C_sort_key=sorted(C.items(), key=lambda x:x[0],reverse=True)
print(count,end='')
for temp in C_sort_key:
    if temp[1]!=0:
        print(" %d %.1f" % (int(temp[0]), float(temp[1])),end='')