diff --git a/Romain.java b/Romain.java
index a3e8441..3fdc5fe 100644
--- a/Romain.java
+++ b/Romain.java
@@ -9,6 +9,31 @@ public class Romain {
   }
 
   public static int convertirEnDecimal(char[] romain) {
+    int cur = 0;
+    int prec = 0;
+    int dec = 0;
+    for (int i = 0; i < romain.length; i++) {
+      prec = cur;
+      cur = asInt(romain[i]);
+      if (prec<cur) {
+        dec -= prec;
+      } else {
+        dec += prec;
+      }
+    }
+    dec+=cur;
+    return dec;
+  }
+
+  public static int asInt(char c) {
+    switch (c) {
+      case 'I':
+        return 1;
+      case 'V':
+        return 5;
+      case 'X':
+        return 10;
+    }
     return 0;
   }