n=int(input())
l=[input().split() for i in range(n)]
t=[]
for i in range(n):
    q=[]
    for j in range(n):
        q.append(l[j][i])
    t.append(q)
c=0
inum=-1
ilis=[]
for i in range(n):
    if 'nyanpass' in t[i] and t[i].count("nyanpass")==n-1:
        c+=1
        ilis.append(i+1)
if c==1:
    inum=ilis[0]
print(inum)