2
1
easy
0
0
1
easy
0
1
1
easy
0
1
1
--
1
1h 5min
0
0
easy
6
6min
1
0
easy
2
1
0
easy
6
0
0
easy
0
1
0
easy
4
0
0
easy
6
0
0
medium
55
30min