added file from first lecture

msg_delivery_blanko.prism

@@ -0,0 +1,13 @@
+dtmc
+
+module msg_delivery
+
+state : [0..3] init 0;
+// s = 0 -> start, s=1 -> try, s=2 -> lost, s=3 -> delivered
+
+[] state = 0  -> (state'=1);
+[] state = 1 -> 1/10 : (state'=2) + 9/10 : (state'=3);
+[] state = 2 -> (state'=1);
+[] state = 3 -> (state'=0);
+
+endmodule