n = int(input())
l=[]
key="nyanpass"
num=0
for i in range(n):
    l.append(input().split())

for j in range(n):
    for i in range(n):
        if l[i][j]=="-":
            continue
        elif l[i][j]!=key:
            break
    else:
        if num==0:
            num=j+1
        else:
            num=-1
if num==0:
    num=-1
print(num)