diff --git a/src/algorithm.c b/src/algorithm.c
index a54b9d0..91b5c10 100755
--- a/src/algorithm.c
+++ b/src/algorithm.c
@@ -381,7 +381,7 @@ void write_to_file(char* filename, creneau* edt, int len_edt) {
     for(int i = 0; i < len_edt; i++) {
         fprintf(ptr, "%d,%d,%d,%d,%d,%d,%s,", edt[i].date.hour, edt[i].date.day, edt[i].date.month, edt[i].date.year, edt[i].length, edt[i].group, edt[i].name);
         if(edt[i].mat == NOTHING) {
-            fprintf(ptr, "_");
+            fprintf(ptr, "none");
         } else if(edt[i].mat == MATH) {
             fprintf(ptr, "Maths");
         } else if(edt[i].mat == PHYSICS) {