#!/usr/bin/env tclsh9.0

set count 0
while {[gets stdin line] >= 0} {
    if {$line eq ""} continue
    set report [split $line " "]
    set decrease 0; set increase 0
    set safe 1
    set curr [lindex $report 0]
    foreach value [lrange $report 1 end] {
        if {$value > $curr} {set increase 1}
        if {$value < $curr} {set decrease 1}
        set dist [expr {abs($value - $curr)}]
        if {$dist < 1 || $dist > 3} {
            set safe 0
            break
        }
        set curr $value
    }
    if {! $safe} continue
    if {$increase && $decrease} continue
    incr count
}
puts $count