N = int(input())
A = [list(map(str,input().split())) for _ in range(N)]

A_inv = list(zip(*A))

ans = -1
for i in range(N):
    if A_inv[i].count("-") + A_inv[i].count("nyanpass") == N:
        if ans == -1:
            ans = i+1
        else:
            ans = -1
            break
print(ans)