N = int(input())
B = []
C = []
for i in range(N) :
    A = list(map(str,input().split()))
    if "nyanpass" in A :
        if A[i] == "nyanpass" :
            B.append(i+1)
    else :
        if A[i] == "-" :
            B.append(i+1)
for j in range(N) :
    c = B.count(j+1)
    C.append(c)
for k in range(N) :
    if C.count(max(C)) >= 2 :
        print(-1)
    else :
        if C[k] == max(C) :
            print(k+1)