Added Euler's totient Function

Others/EulersFunction.java

@@ -0,0 +1,21 @@
+// You can read more about Euler's totient function 
+// https://en.wikipedia.org/wiki/Euler%27s_totient_function
+public class EulersFunction {
+    // This method returns us number of x that (x < n) and gcd(x, n) == 1 in O(sqrt(n)) time complexity;
+    public static int getEuler(int n) {
+        int result = n;
+        for (int i = 2; i * i <= n; i++) {
+            if(n % i == 0) {
+                while (n % i == 0) n /= i;
+                result -= result / i;
+            }
+        }
+        if (n > 1) result -= result / n;
+        return result;
+    }
+    public static void main(String[] args) {
+        for (int i = 1; i < 100; i++) {
+            System.out.println(getEuler(i));
+        }
+    }
+}