diff --git a/honoka/plugins/simpleprediction.cpp b/honoka/plugins/simpleprediction.cpp
index 637910f..c3257b8 100644
--- a/honoka/plugins/simpleprediction.cpp
+++ b/honoka/plugins/simpleprediction.cpp
@@ -44,7 +44,7 @@
 SimplePrediction::SimplePrediction(ConfigPointer cfg) : Predictor(cfg)
 {
     size = cfg->read(HONOKA_CONFIG_SIMPLEPREDICTION_SIZE,HONOKA_DEFAULT_SIMPLEPREDICTION_SIZE);
-    if (size < 0) size = 0;
+    if (size < 1) size = HONOKA_DEFAULT_SIMPLEPREDICTION_SIZE;
 }
 
 
@@ -125,8 +125,8 @@
 void SimplePrediction::update(const WideString str,const WideString yomi)
 {
     if ((!yomi.length()) || (!str.length())) return;
-    for(multimap<WideString,WideString>::iterator it = data.find(yomi);it != data.end();data.find(yomi))
-        if (it->second == str) return;
+    for(multimap<WideString,WideString>::iterator it = data.begin();it != data.end();it++)
+        if ((it->first == yomi) &&(it->second == str)) return;
     data.insert(pair<WideString,WideString>(yomi,str));
     if (data.size() > size) data.erase(data.begin());
     return;