def main():
    n = int(input())
    ren = []
    for i in range(n):
        l = input().split()
        count = 0
        for e in l:
            if e == "nyanpass":
                ren.append(count)
            count += 1
    #print(ren)
    ren_set = set(ren)
    #print(ren_set)
    if len(ren_set) == 1:
        for e in ren_set:
            print(e)
    else:
        print(-1)

if __name__ == '__main__':
    main()