def nyan(N: int, array):
    nyan = []
    for i in range(N):
        for j in range(N):
            if array[i][j] == "nyanpass":
                if not j+1 in nyan:
                    nyan.append(j+1)
            else:
                if j+1 in array:
                    nyan.remove(j+1)
    if len(nyan) == 1:
        return nyan[0]
    else:
        return -1
        
N = int(input())
array = []
array_line = input().split()
for i in range(N):
	array_row = []
	for j in range(N):
		array_row.append(array_line[j])
	array.append(array_row)