How many entries are there in the Left 4 Dead series?
2
3
3
2
3
2
4
3
5
2
4
3
5
2
4
3
5
2
4
3
5
2
4
3
5
2
4
3
1
5
2
4
3
1
5
2
4
3
1
5
2
4
3
1
6
5
0
2
4
3
1
6
5
7
2
4
3
1
6
5
7
2
4
3
1
6
5
7
2
4
3
1
6
5
7
2
4
3
8
1
6
5
7
2
4
3
8
1
6
5
7
2
4
3
8
1
6
5
7
2
4
3
8
1
6
5
7
9
2
4
8
1
6
5
7
9
10
2
4
11
8
1
6
5
7
9
10
13
4
11
8
1
6
5
7
9
10
13
11
8
1
6
7
9
10
13
11
8
1
6
7
9
10
13
12
11
8
1
6
7
9
10
13
12
11
8
1
6
7
9
10
16
13
12
11
8
1
6
7
9
10
16
13
12
11
8
6
7
9
10
16
13
66
62
59
57
63
102
58
132