diff --git a/src/11/18/P1545.cpp b/src/11/18/P1545.cpp
index 0c4244a..1224f89 100644
--- a/src/11/18/P1545.cpp
+++ b/src/11/18/P1545.cpp
@@ -5,7 +5,7 @@
 #include <istream>
 #include <vector>
 using ll = int64_t;
-// #define printf
+#define printf
 const ll inf=1e9+7;
 ll n,l,a,b;
 std::vector<ll> v,dp,diff;
@@ -23,9 +23,10 @@ int main(){
         diff[e]++;
     }
     dp[0]=0;
-    for(ll i=1;i<=l;i++){
+    for(int i=2;i<=l;i+=2){
+        v[i-1]+=v[i-2];
         v[i]+=v[i-1];
-        for(ll j=a;j<=b&&i-j*2>=0;j++){
+        for(int j=a;j<=b&&i-j*2>=0;j++){
             if(!v[i-j*2] || diff[i-j*2]==v[i-j*2-1]){
                 dp[i]=std::min(dp[i],dp[i-j*2]+1);
             }
@@ -35,5 +36,5 @@ int main(){
         printf("diff[%lld]=%lld\n",i,diff[i]);
         printf("\n");
     }
-    std::cout<<dp[l]<<"\n";
+    std::cout<<(dp[l]>=inf?-1:dp[l])<<"\n";
 }
\ No newline at end of file