diff --git a/app/build.gradle b/app/build.gradle
index 9a94bed..1135d4c 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -37,7 +37,8 @@
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
     implementation 'com.android.support:appcompat-v7:26.1.0'
     implementation 'com.android.support.constraint:constraint-layout:1.0.2'
-    implementation 'com.google.firebase:firebase-core:11.6.0'
+    implementation "com.google.firebase:firebase-core:${play_service_version}"
+    implementation "com.google.android.gms:play-services-ads:${play_service_version}"
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'com.android.support.test:runner:1.0.1'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
@@ -54,5 +55,4 @@
     annotationProcessor "android.arch.lifecycle:compiler:1.0.0-rc1"
 }
 
-
 apply plugin: 'com.google.gms.google-services'
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
index 64e08bf..d9286e0 100644
--- a/build.gradle
+++ b/build.gradle
@@ -3,6 +3,7 @@
 buildscript {
     ext.kotlin_version = '1.1.51'
     ext.realm_version = '3.3.2'
+    ext.play_service_version = '11.4.2'
     repositories {
         google()
         jcenter()