n = int(input())
matrix = []
r = -1
c = -1

for i in range(n):
    row = input().split()
    for j in range(n):
        if row[j] == '?':
            r = i
            c = j
    matrix.append(row)

if n == 1:
    print(1)
else:
    x = None
    valid = True
    for l in range(n):
        if l == c:
            continue
        sum_part = 0
        coeff = None
        for i in range(n):
            if i == r:
                coeff_val = matrix[i][l]
                coeff = int(coeff_val)
                continue
            val_c = matrix[i][c]
            val_l = matrix[i][l]
            sum_part += int(val_c) * int(val_l)
        if coeff == 0:
            if sum_part != 0:
                valid = False
                break
        else:
            if (-sum_part) % coeff != 0:
                valid = False
                break
            current_x = (-sum_part) // coeff
            if x is None:
                x = current_x
            else:
                if current_x != x:
                    valid = False
                    break
    print(x)