gcd() {
    local _n=$1 _m=$2
    if (( _n % _m == 0 )); then
        echo "$_m"
        return
    fi
    gcd "$_m" $(( _n % _m ))
}

remove_common_prime_divisors() {
    local _n=$1 _m=$2 _d
    while (( _n != 1 )); do
        _d=$(gcd "$_n" "$_m")
        if (( _d == 1 )); then
            break
        fi
        _n=$(( _n / _d ))
    done
    echo "$_n"
}

common_prime_divisors() {
    local -n _arrA="$1"
    local -n _arrB="$2"
    local _counter=0 _i _x _y _d _rx _ry
    for _i in "${!_arrA[@]}"; do
        _x=${_arrA[$_i]}
        _y=${_arrB[$_i]}
        _d=$(gcd "$_x" "$_y")
        _rx=$(remove_common_prime_divisors "$_x" "$_d")
        if (( _rx != 1 )); then
            continue
        fi
        _ry=$(remove_common_prime_divisors "$_y" "$_d")
        if (( _ry == 1 )); then
            ((_counter++))
        fi
    done
    echo "$_counter"
}