diff --git a/io.c b/io.c
index b158637d15856b8384cf4dd27d3b8bafbfda8a9d..7df667f2c5f38eea2e04ca573b49518db315a408 100644
--- a/io.c
+++ b/io.c
@@ -1,5 +1,5 @@
 /* io.c */
-/* Last Change: 2019/06/02 (Sun) 23:53:02. */
+/* Last Change: 2019/06/03 (Mon) 06:32:01. */
 
 #include<stdio.h>
 #include"io.h"
@@ -59,9 +59,11 @@ void read_problem(void){
 			nowx=num=0;
 			gets(str);
 			for(k=0;;k++){
-				if(str[k]=='*')
+				if(str[k]=='0')
 					num=-1;
-				else if('0'<=str[k]&&str[k]<='9')
+				else if(str[k]=='+')
+					num=0;
+				else if('1'<=str[k]&&str[k]<='9')
 					num=num*10+str[k]-'0';
 				else if(str[k]==','){
 					if(num<0){