input1=[eval(i) for i in input().split()]
input2=[eval(i) for i in input().split()]
d = {}
#查找键值的时候顺便合并同类项
for i in range(input1[0]):
a = i*2+1
d[input1[a]] = input1[a+1]+d.get(input1[a],0)
for i in range(input2[0]):
a = i*2+1
d[input2[a]] = input2[a+1]+d.get(input2[a],0)
#去掉系数为0的
for i in list(d.keys()):
if d[i] == 0:
del d[i]
#将x[1]之后的按照键值排序,默认从小到大
d = sorted(d.items(),key=lambda x:x[0],reverse=True)
print(len(d),end="")
for x,y in d:
print(" {} {:.1f}".format(x,y),end="")