diff --git a/main.go b/main.go
index ff15b32..61abe6c 100644
--- a/main.go
+++ b/main.go
@@ -33,6 +33,14 @@ func main() {
 	for i := range fields {
 		fields[i] = strings.TrimSpace(fields[i])
 	}
+	for i := range fields {
+		for j := i + 1; j < len(fields); j++ {
+			if fields[i] == fields[j] {
+				fields[i] = fmt.Sprintf("%s[%d]", fields[i], i)
+				fields[j] = fmt.Sprintf("%s[%d]", fields[j], j)
+			}
+		}
+	}
 	n := 0
 	for {
 		n += 1
@@ -55,6 +63,9 @@ func main() {
 			if i < len(fields) {
 				k = fields[i]
 			}
+			if _, ok := lineResult[k]; ok {
+				k = fmt.Sprintf("%s[%d]", k, i)
+			}
 			lineResult[k] = strings.TrimSpace(line[i])
 		}
 		b, _ := json.Marshal(lineResult)