n=int(input())
m=[input().split(" ") for i in range(n)]
def f(w):
    for i in range(n):
        if m[i][w]=="-":
            continue
        if m[i][w]!="nyanpass":
            return False
    return True
#
g,num=False,-1
for i in range(n):
    if f(i)==True and g==False:
        num=i+1
        g=True
    elif f(i)==True and g==True:
        num=-1
        break
#
print(num)