#include <stdio.h>
#include <list>
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <sstream>

using namespace std;

enum Direction {
    UP,
    DOWN,
    UNSET
}; 

int main(){
    string line;
    int safeReports = 0;
    stringstream wholeDoc;

    ifstream puzzle("input.txt", ifstream::in);

        while (getline(puzzle, line)) {
            istringstream lineStream(line);
            string numberString;
            list<int> currentLevels;
            while (getline(lineStream, numberString, ' ')) {
                int number = stoi(numberString);
                currentLevels.push_back(number);
            }

            int numOfLevelsInLine = currentLevels.size();
            int numOfLevelsProcessed = 0;
            auto curListIt = currentLevels.begin();
            curListIt++; //point to second item in list
            auto RevCurListIt = currentLevels.rbegin();
            RevCurListIt++; //points to second to last item
            enum Direction dir; 
            bool listDirty =false;
            list<int>changeFromPrevLevel;
            list<int>levelGoesUp;
            list<int>levelGoDown;
            list<int>levelStaysSame;
            int totalChange=0;
            
            changeFromPrevLevel.push_front(0);
            auto frontIt = currentLevels.begin();
            frontIt++;
            auto backIt = currentLevels.begin();

            for(int index = 1;frontIt!=currentLevels.end();index++){
                int change = (*backIt)-(*frontIt);
                totalChange+=change;
                changeFromPrevLevel.push_back(change);
                frontIt++;
                backIt++;
                if (change>0){
                    levelGoesUp.push_front(index);
                } else if(change<0){
                    levelGoDown.push_front(index);
                } else {
                    levelStaysSame.push_front(index);
                }
            }
            float averageChange = totalChange/(currentLevels.size()-1);
            //need to pull the first one to have something to compare to

            int prevlevel = currentLevels.front();
            currentLevels.pop_front();
            numOfLevelsProcessed++;
            if (prevlevel < currentLevels.front()){
                dir = DOWN;
            } else if (prevlevel > currentLevels.front()){
                dir = UP;
            } else {
                currentLevels.clear();
            }
            

            for (int level = currentLevels.front(); !currentLevels.empty();level=currentLevels.front()){
                if (abs(prevlevel-level)>3) {currentLevels.clear();break;}
                if(prevlevel==level){ currentLevels.clear();break;}
                if(dir==UP&&(prevlevel<currentLevels.front())) {currentLevels.clear();break;}
                if(dir==DOWN&&(prevlevel>currentLevels.front())) {currentLevels.clear();break;}
                
                prevlevel=currentLevels.front();
                currentLevels.pop_front();
                numOfLevelsProcessed++;

                if(numOfLevelsProcessed==numOfLevelsInLine){
                    safeReports++;
                }
            }
        }
cout << safeReports;
puzzle.close();
}