n=int(input())
b=[]
for h in range(n+2):
    b.append("x")
a=[]
a.append(b)
c=[]
for i in range(n):
    c=[]
    c.append("x")
    r=list(input())
    for l in range(n):
        c.append(r[l])
    c.append("x")
    a.append(c)
a.append(b)
x=0
y=0
m=0
q=0
for v in range(n):
    y=y+1
    x=0
    for e in range(n):
        x=x+1
        if a[x+1][y]=="o":
            m=m+1
        if a[x-1][y]=="o":
            m=m+1
        if a[x][y+1]=="o":
            m=m+1
        if a[x][y-1]=="o":
            m=m=1
        if m%2==1:
            q=q+1
if q%2==1:
    print("YES")
else:
    print("NO")

 for h in range(n+2)

 c=[]
for i in range(n):
    c=[]
    c.append("x")
    r=list(input())

 x=0
y=0
m=0
q=0