import java.io.BufferedInputStream;
import java.io.IOException;

public class Main {

    static class Entrada {
        private final BufferedInputStream in =
                new BufferedInputStream(System.in);

        int leerEntero() throws IOException {
            int c;

            do {
                c = in.read();
            } while (c <= 32 && c != -1);

            int num = 0;

            while (c > 32) {
                num = num * 10 + c - '0';
                c = in.read();
            }

            return num;
        }
    }

    static int calcularMCD(int a, int b) {
        while (b != 0) {
            int resto = a % b;
            a = b;
            b = resto;
        }

        return Math.abs(a);
    }

    static int calcularOp(int[] a) {
        int operaciones = 0;
        int n = a.length;

        for (int i = 0; i < n - 1; i++) {
            if (a[i] % 2 != 0) {
                if (a[i + 1] % 2 != 0) {
                    operaciones++;
                    i++;
                } else {
                    operaciones += 2;
                }
            }
        }

        return operaciones;
    }

    public static void main(String[] args) throws Exception {
        Entrada entrada = new Entrada();

        int n = entrada.leerEntero();
        int[] a = new int[n];
        int mcd = 0;

        for (int i = 0; i < n; i++) {
            a[i] = entrada.leerEntero();
            mcd = calcularMCD(mcd, a[i]);
        }

        if (mcd > 1) {
            System.out.println("YES");
            System.out.println(0);
        } else {
            System.out.println("YES");
            System.out.println(calcularOp(a));
        }
    }
}