Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Season | Network | Play-by-play | Color commentator(s) | Sideline reporter(s) |
| --- | --- | --- | --- | --- |
| 1969 | CBS | Jack Whitaker | Frank Gifford and Don Perkins |  |
| 1968 | CBS | Ray Scott | Paul Christman | Frank Glieber |
| 1967 | CBS | Frank Glieber | Frank Gifford |  |
| 1966 | CBS | Chuck Thompson | Tom Brookshier |  |
| 1965 | CBS | Frank Glieber (first half) and Chuck Thompson (second half) | Pat Summerall |  |
| 1964 | CBS | Jack Drees (first half) and Earl Gillespie (second half) | Frank Gifford |  |
| 1963 | CBS | Ray Scott (first half) and Ken Coleman (second half) | Frank Gifford |  |
| 1962 | CBS | Chris Schenkel (first half) and Ray Scott (second half) | Warren Lahr |  |
| 1961 | CBS | Chris Schenkel (first half) and Van Patrick (second half) | Johnny Lujack |  |
Question:
how many broadcasters performed at least twice?
Answer:
3