# 4.有一个字典a={1:2,2:3,3:5},求字典键的和，键所对应的值的和，请写出代码
a = {1: 2, 2: 3, 3: 5}
# 方法1：
b = c = 0
for key,value in a.items():
b += key
c += value
print(b,c)
# 方法2：
b = c = 0
for key,value in a.items():
b,c = b + key,c+value
print(b,c)
# 方法3：
print(sum(a.keys()))
print(sum(a.values()))