8

#include <iostream>
#include <string>
#include <algorithm>
#include <vector>

using namespace std;

bool pred(int a)
{
    int cntOfChet = 0, cntOfNechet = 0;
    while(a){
        if((a % 10) % 2 == 0){
            cntOfChet++;
        }else{
            cntOfNechet++;
        }
        a /= 10;
    }
    if(cntOfChet == cntOfNechet){
        return true;
    }else{
        return false;
    }
}

int main()
{
    vector<int> v;
    int x;
    while(cin >> x){
        v.push_back(x);
    }
    cout << count_if(v.begin(), v.end(), pred);
    return 0;
}