[SOLVED] How I change the compileSdkVersion in build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"
    defaultConfig {
        applicationId 'it.polimi.deib.p2pchat'
        minSdkVersion 19
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }
    productFlavors {
    }
}

task wrapper(type: Wrapper) {
    gradleVersion = "2.5"
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    provided 'org.projectlombok:lombok:1.16.4'
    compile 'com.android.support:appcompat-v7:22.2.1'
    compile 'com.android.support:support-v4:22.2.1'
    compile 'com.android.support:recyclerview-v7:22.2.1'
    compile 'com.android.support:cardview-v7:22.2.1'
    compile 'com.jpardogo.materialtabstrip:library:1.0.6'
}