john? >> dickerson: thank you. manny, tonight for us in brazil. today the departments of defense and veterans affairs began an important meeting in nashville to discuss new ways to prevent slitary suicides. about 20 veterans take their own lives each day. a hotline launched in 2007 has answered more than 3.5 million calls sending emergency help to nearly 100,000 people. dean reynolds gives us an inside look. >> are you having any suicidal thoughts today? have you ever attempted suicide? >> reporter: at the veteran's crisis line in canandaigua, new york, the calls come in all day and all night. >> can you put the knife in a safe place? >> what did you do with the nail gun? >> reporter: 1700 calls every day from veterans on the brink. cbs news was given rare access to the v.a.'s responders and their literally life-saving conversations. >> right now, you are having thoughts of suicide and attempts to end your life. so i want to get somebody out to