int input int for in input split for in range for in range for in rang

a = int(input())
n = 0
A = [[int(j) for j in input().split()] for i in range(a)]
for i in range(a):
    for j in range(a):
        if (A[i][j]==1):
            n+=1
            A[j][i]=0
print(n)