diff --git a/graph/dinic.cc b/graph/dinic.cc
index 0766e28..d638692 100644
--- a/graph/dinic.cc
+++ b/graph/dinic.cc
@@ -13,7 +13,7 @@ struct dinic {
 
     dinic(int n) : edges(n + 1), layer(n + 1), vis(n + 1) {}
 
-    void add_edge(int from, int to, ll cap, int mark = false) {
+    void add_edge(int from, int to, ll cap, int mark = 0) {
         edges[from].push_back({ to, cap, 0, int(edges[to].size()), mark });
         edges[to].push_back({ from, 0, 0, int(edges[from].size() - 1), mark });
     }