N = 3
S = [input() for _ in range(N)]

ans = "No"
M = S[1][1]
if S[0][0]==M and S[0][2]==M and S[0][1]!=M:
    if S[1][0]!=M and S[1][2]!=M:
        if S[2][0]==M and S[2][2]==M and S[2][1]!=M:
            ans="Yes"

print(ans)