@GET("site.get.pagescount.php")
 Call<Integer> getCountPages(@Query("token") String token);

Retrofit retrofit = new Retrofit.Builder()
        .baseUrl(CFG.ENDPOINT)
        //.addConverterFactory(GsonConverterFactory.create(gson))
        /*код скопипасчен с реализации запроса, который получает JSON*/
        .build();
API api = retrofit.create(API.class);
Call<Page> call = api.getCountPages(CFG.TOKEN);
Responce<Integer> b = call.execute();

FATAL EXCEPTION: main
Process: ru.idaspin.site, PID: 21496
android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147)
at java.net.InetAddress.lookupHostByName(InetAddress.java:418)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
at java.net.InetAddress.getAllByName(InetAddress.java:215)
at okhttp3.Dns$1.lookup(Dns.java:39)
at okhttp3.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:173)
at okhttp3.internal.http.RouteSelector.nextProxy(RouteSelector.java:139)
at okhttp3.internal.http.RouteSelector.next(RouteSelector.java:81)
at okhttp3.internal.http.StreamAllocation.findConnection(StreamAllocation.java:172)
at okhttp3.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:123)
at okhttp3.internal.http.StreamAllocation.newStream(StreamAllocation.java:93)
at okhttp3.internal.http.HttpEngine.connect(HttpEngine.java:296)
at okhttp3.internal.http.HttpEngine.sendRequest(HttpEngine.java:248)
at okhttp3.RealCall.getResponse(RealCall.java:243)
at okhttp3.RealCall$ApplicationInterceptorChain.proceed(RealCall.java:201)
at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:163)
at okhttp3.RealCall.execute(RealCall.java:57)
at retrofit2.OkHttpCall.execute(OkHttpCall.java:174)
at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall.execute(ExecutorCallAdapterFactory.java:89)
at ru.idaspin.site.Fragments.HomeFragment.nextPage(HomeFragment.java:240)
...

Call<ResponseBody> call = api.getInteger(foo);
call.enqueue(new Callback<ResponseBody>() {

    @Override
    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
        int value = Integer.parseInt(response.body().toString());
    }

    @Override
    public void onFailure(Call<Integer> call, Throwable t) {
        //Do something with failure
    }
});