func totient(n) {
    var tot = n
    var i = 2
    while i * i <= n {
        if n % i == 0 {
            while n % i == 0 {
                n /= i
            }
            tot -= tot / i
        }
        if i == 2 {
            i = 1
        }
        i += 2
    }
    if n > 1 {
        tot -= tot / n
    }
    return tot
}

print("n\tphi\tprime")
var count = 0
for n in 1..25 {
    var tot = totient(n)
    var isPrime = n - 1 == tot
    if isPrime {
        count += 1
    }
    print("\(n)\t\(tot)\t\(isPrime)")
}
print("\nNumber of primes up to 25 \t= \(count)")
for n in 26..100000 {
    var tot = totient(n)
    if tot == n - 1 {
        count += 1
    }
    if n == 100 || n == 1000 || n % 10000 == 0 {
        print("Number of primes up to \(n) \t= \(count)")
    }
}