题解 | #矩阵计算#
矩阵计算
https://www.nowcoder.com/practice/0c83231923c541d2aa15861571831ee5
n,m = map(int,input().split())
list1=[]
list2=[]
for i in range(n):
a=list(map(int,input().split()))
list1.extend(a)
for j in list1:
if j>0:
list2.append(j)
print(sum(list2))
