# python3 code .
def seq(arr):
if len(arr) <= 2:
return len(arr)
else :
ans = 2;
tmp_ans = 2;
for i in range(2 , len(arr)):
if arr[i]==arr[i-2]:
tmp_ans = tmp_ans + 1
else :
tmp_ans = 2
ans = max(ans , tmp_ans)
return ans
l = [7 , -5 , -5 , -5 , 7 , -1 , 7];
print(seq(l))
CiMgcHl0aG9uMyBjb2RlIC4KZGVmIHNlcShhcnIpOgoJaWYgbGVuKGFycikgPD0gMjoKCQlyZXR1cm4gbGVuKGFycikKCWVsc2UgOgoJCWFucyA9IDI7CgkJdG1wX2FucyA9IDI7CgkJZm9yIGkgaW4gcmFuZ2UoMiAsIGxlbihhcnIpKToKCQkJaWYgYXJyW2ldPT1hcnJbaS0yXToKCQkJCXRtcF9hbnMgPSB0bXBfYW5zICsgMQoJCQllbHNlIDoKCQkJCXRtcF9hbnMgPSAyCgoJCQlhbnMgPSBtYXgoYW5zICwgdG1wX2FucykKCQlyZXR1cm4gYW5zCgoKbCA9IFs3ICwgLTUgLCAtNSAsIC01ICwgNyAsIC0xICwgN107CnByaW50KHNlcShsKSk=