How many Half-Life games are there?
2
2
4
3
5
2
4
3
5
2
4
3
5
2
4
3
5
2
4
3
5
2
4
3
5
2
4
3
5
2
6
4
3
5
2
6
4
3
7
5
2
6
4
1
3
7
5
2
6
4
1
3
7
5
2
6
4
1
3
7
5
2
6
4
1
3
7
5
2
6
4
1
3
7
5
2
6
4
1
3
7
5
8
2
6
4
1
3
7
5
8
2
6
4
1
3
7
0
5
8
2
6
4
1
3
7
5
8
0
2
6
4
1
3
7
5
8
2
6
0
4
1
3
7
5
8
6
1
7
9
8
6
1
10
7
9
8
6
1
10
7
9
8
6
1
10
7
9
8
6
1
10
7
9
8
6
1
10
7
9
8
13
6
1
10
7
9
8
13
1
10
7
9
8
13
1
10
9
8
13
10
9
8
13
10
9
8
13
10
12
9
8
13
14
10
12
9
8
ten
ten
ten