diff --git a/src/main.rs b/src/main.rs
index 75d9a58..7d5d055 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -51,6 +51,7 @@ fn add(f: &String, x: &Option<String>, tag: &Option<String>) -> Result<(), Strin
 #[derive(Debug, Serialize, Clone)]
 struct Log {
    t: String,
+   d: u8,
    xs: Vec<LogX>,
 }
 #[derive(Debug, Serialize, Clone)]
@@ -66,25 +67,30 @@ fn log(f: &String, since: &Option<String>) -> Result<(), String> {
    let tsheet = tsheet.sorted();
 
    let mut result = vec![];
-   let mut curr = Log{t: "".to_string(), xs: vec![]};
-   for x in &tsheet.xs {
+   let mut curr = Log{t: "".to_string(), d: 0, xs: vec![]};
+   for i in 0..tsheet.xs.len() {
+      let x = &tsheet.xs[i];
       if curr.t != x.timestamp() {
          if curr.xs.len() > 0 {
             result.push(curr.clone());
          }
          curr.xs.truncate(0);
          curr.t = x.timestamp();
+         curr.d = 0;
       }
+      let d = match curr.xs.len() {
+         0 => 1,
+         _ => ((tsheet.xs[i].t - tsheet.xs[i-1].t + 60*30) / (60*60)) as u8,
+      };
       curr.t = x.timestamp();
-      curr.xs.push(LogX{d: 0, x: x.x.clone()});
+      curr.xs.push(LogX{d: d, x: x.x.clone()});
+      curr.d += d;
    }
    if curr.xs.len() > 0 {
       result.push(curr.clone());
    }
-
    println!("{}", serde_yaml::to_string(&result).unwrap());
-
-   Err("not impl".to_string())
+   Ok(())
 }
 
 fn parse_time(since: &Option<String>) -> Result<SystemTime, String> {