def tarjan(V, E):
    i = 0
    S = []
    index = {}
    lowlink = {}
    stackset = set()
    components = []

    def strongconnect(v):
        nonlocal i
        index[v] = i
        lowlink[v] = i
        i += 1
        S.append(v)
        stackset.add(v)

        for w in E[v]:
            if w not in index:
                strongconnect(w)
                lowlink[v] = min(lowlink[v], lowlink[w])
            elif w in stackset:
                lowlink[v] = min(lowlink[v], index[w])

        if lowlink[v] == index[v]:
            component = []
            components.append(component)
            while True:
                w = S.pop()
                stackset.remove(w)
                component.append(w)
                if w == v:
                    break

    for v in V:
        if v not in index:
            strongconnect(v)

    return components[::-1]


N = int(input())
successors = {}
for i in range(N):
    line = input()
    successors[i] = [j for j, c in enumerate(line)
                    if c == '1']

vertices = range(N)
components = tarjan(vertices, successors)
last_component = components[-1]
if 0 not in last_component:
    print("impossible")
else:
    import itertools
    from collections import deque

    joined = list(itertools.chain(components[:-1]))
    last_component = deque(last_component)
    while last_component[-1] != 0:
        last_component.rotate(1)

    joined += list(last_component)
    print(*joined)