diff --git a/content.yml b/content.yml
index 65645cd..79d9c02 100644
--- a/content.yml
+++ b/content.yml
@@ -449,19 +449,33 @@ home:
           The inputs are provided in US English for the city and country 
           names, without diacritics. On each line, the city and country 
           names must be separated by a comma. Pasting a csv file in the 
-          form is possible. Two types of inputs can be considered 
+          form is possible, provided that a comma separates
+          the city and country names. 
+
+          A round trip is defined by a city pair. If the user enters cityA as 
+          the origin city, and twice cityB as destinations, the tool returns 
+          the cumulative emission and distance from two round trips 
+          involving cityA and cityB, and indicates that 2 round trips were involved.
+          The same happens if the user enters twice cityA as the city of origin 
+          and cityB as the sole destination. 
+
+          Three types of inputs can be considered 
           depending on whether the user wants an “individual” estimate 
           or an estimate for a conference, meeting and so on. In the 
           former case, the “origin” city is unique and the “destination” 
-          cities multiple. In the later case, the “origin” cities are multiple 
+          cities may be multiple. The tool returns the carbon dioxide 
+          equivalent emission for each city of destination. 
+          In the later case, the “origin” cities are multiple 
           (i.e. the cities from which the participants to the conference 
-          depart from), and the “destination” city may a single host city 
+          depart from), and the “destination” city may be a single host city 
           or multiple host cities if the user wants to compare their 
-          associated footprint. Cities found identical in the input form are 
-          always grouped, and their number in the group is given by the 
-          number of trips in the output, and the distance given is the 
-          cumulative distance over the group. 
- 
+          associated footprint. If there is one destination, the tool returns 
+          the carbon dioxide equivalent for each city of origin. If multiple 
+          destinations are provided the tool returns the carbon dioxide 
+          equivalent emission summed over all cities of 
+          origin and for each city of destination. The cumulative distance to 
+          each city of destination is also provided. 
+
           The result pages provides a summary plot which can be 
           downloaded, as well as a csv and raw yaml file. The csv file 
           lists the name of the city as in the form, the address to which it 
@@ -471,7 +485,6 @@ home:
           e.g. 300 km) and the number of trips by plane. The plot and the 
           csv file rank the cities against the carbon dioxide emissions. 
 
-
       - title: Trouble shooting
         content: |
           The estimation can go wrong if a city is not properly 
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libgit2 0.21.2