@@ -0,0 +1,579 @@
+import java.util.BitSet;%0Aimport java.util.stream.LongStream;%0A%0A@SuppressWarnings(%22unused%22)%0Apublic class P072 implements Puzzle %7B%0A%0A    @Override%0A    public String solve() %7B%0A        final BitSet primesBits = Util.primesBits(1_000_000);%0A        return %22%22 + LongStream.range(2, 1_000_001)%0A                .parallel()%0A                .map(i -%3E phi((int) i, primesBits))%0A                .sum();%0A    %7D%0A%0A    // Euler's Totient Function%0A    long phi(long n, BitSet primeBits) %7B%0A        return Util.uniqueFactors((int) n, primeBits).reduce(n, (product, i) -%3E product * (i - 1) / i);%0A    %7D%0A%7D

add 72