Solution

#include <iostream>
using namespace std;

int main()
{
    int O = 0, E = 0, N, x;
    cin >> N;
    for (int i = 0; i < N; i++) {
        cin >> x;
        if (x % 2 == 0) E++; else O++;
    }
    while (O > E) { O = O - 2; E++; }
    if (E > O + 1) E = O + 1;
    cout << E + O << "\n";
}