a = int()
        promedio = int()
        i = int()
        j = int()
        a = [[int() for ind0 in range(3)] for ind1 in range(3)]
        promedio = 0
        for i in range(1,4):
            for j in range(1,4):
                a[i-1][j-1] = int(input())
                if i==j:
                    promedio = promedio+a[i-1][j-1]/a[i-1][j-1]
        print(" el promedio es ",promedio)