diff --git a/src/main/kotlin/hu/obuda/devops/fibonaccirestapi/controller/FibonacciController.kt b/src/main/kotlin/hu/obuda/devops/fibonaccirestapi/controller/FibonacciController.kt
index 35c9112..bcc23bb 100644
--- a/src/main/kotlin/hu/obuda/devops/fibonaccirestapi/controller/FibonacciController.kt
+++ b/src/main/kotlin/hu/obuda/devops/fibonaccirestapi/controller/FibonacciController.kt
@@ -2,10 +2,12 @@ package hu.obuda.devops.fibonaccirestapi.controller
 
 import hu.obuda.devops.fibonaccirestapi.service.FibonacciService
 import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.http.HttpStatus
 import org.springframework.web.bind.annotation.GetMapping
 import org.springframework.web.bind.annotation.RequestMapping
 import org.springframework.web.bind.annotation.RequestParam
 import org.springframework.web.bind.annotation.RestController
+import org.springframework.web.server.ResponseStatusException
 
 @RestController
 @RequestMapping("/")
@@ -16,7 +18,10 @@ class FibonacciController {
 
     @GetMapping(value = ["fibonacci"])
     open fun fibonacci(@RequestParam n: Int): Int? {
-        // TODO - If n is greater than 46 then return BAD REQUEST use HttpStatus
+        if (n > 46) {
+            throw ResponseStatusException(HttpStatus.BAD_REQUEST, "n must be <= 46")
+        }
+
         return fibonacciService?.fibonacci(n)
     }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/hu/obuda/devops/fibonaccirestapi/service/FibonacciService.kt b/src/main/kotlin/hu/obuda/devops/fibonaccirestapi/service/FibonacciService.kt
index 137941a..e19ffd7 100644
--- a/src/main/kotlin/hu/obuda/devops/fibonaccirestapi/service/FibonacciService.kt
+++ b/src/main/kotlin/hu/obuda/devops/fibonaccirestapi/service/FibonacciService.kt
@@ -5,7 +5,11 @@ import org.springframework.stereotype.Service
 @Service
 class FibonacciService {
     fun fibonacci(n: Int): Int {
-        return if (n == 1) 0
-        else 0 // TODO instead of this logic implement fibonacci
+      return when {
+          n < 0 -> 0
+          n == 0 -> 0
+          n == 1 -> 1
+          else -> fibonacci(n - 1) + fibonacci(n - 2)
+      }
     }
 }
\ No newline at end of file
diff --git a/src/test/kotlin/hu/obuda/devops/fibonaccirestapi/integration/IntegrationTest.kt b/src/test/kotlin/hu/obuda/devops/fibonaccirestapi/integration/IntegrationTest.kt
index f0579d3..2853085 100644
--- a/src/test/kotlin/hu/obuda/devops/fibonaccirestapi/integration/IntegrationTest.kt
+++ b/src/test/kotlin/hu/obuda/devops/fibonaccirestapi/integration/IntegrationTest.kt
@@ -27,6 +27,21 @@ class IntegrationTest {
         Assertions.assertEquals("1", entity.body)
     }
 
+    @Test
+    fun callFibonacciEndpoint2() {
+        // given
+
+        // when
+        val entity = restTemplate.getForEntity(
+            "http://localhost:8080/fibonacci?n=46",
+            String::class.java
+        )
+
+        // then
+        Assertions.assertEquals(HttpStatus.OK, entity.statusCode)
+        Assertions.assertEquals("1836311903", entity.body)
+    }
+
     @Test
     @Throws(Exception::class)
     fun callFibonacciEndpointWithInvalid() {
diff --git a/src/test/kotlin/hu/obuda/devops/fibonaccirestapi/service/FibonacciServiceTest.kt b/src/test/kotlin/hu/obuda/devops/fibonaccirestapi/service/FibonacciServiceTest.kt
index fc46305..72a52b0 100644
--- a/src/test/kotlin/hu/obuda/devops/fibonaccirestapi/service/FibonacciServiceTest.kt
+++ b/src/test/kotlin/hu/obuda/devops/fibonaccirestapi/service/FibonacciServiceTest.kt
@@ -19,4 +19,22 @@ class FibonacciServiceTest {
     }
 
     // TODO - Test with greater numbers and test edge cases
+
+    @Test
+    fun shouldReturn0WhenCallMinus1() {
+        val result: Int = underTest.fibonacci(-1)
+        Assertions.assertEquals(0, result)
+    }
+
+    @Test
+    fun shouldReturn1WhenCall2() {
+        val result: Int = underTest.fibonacci(2)
+        Assertions.assertEquals(1, result)
+    }
+
+    @Test
+    fun shouldReturn2WhenCall3() {
+        val result: Int = underTest.fibonacci(3)
+        Assertions.assertEquals(2, result)
+    }
 }
\ No newline at end of file