diff --git a/13307130285/12.15/1.cpp b/13307130285/12.15/1.cpp
new file mode 100644
index 0000000..b355780
--- /dev/null
+++ b/13307130285/12.15/1.cpp
@@ -0,0 +1,88 @@
+#include <cstdio>
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+using namespace std;
+
+int a[30];
+//a[letter-'A']=num
+string s[15];
+//words
+int temp;
+//first letter appear -'A'
+bool use[10];
+//true:has used
+ //false:not used yet  
+int number=0;
+long long x[15];
+int n;
+int uuuu=0;
+
+bool check()
+{
+	memset(x,0,sizeof(x));
+	int sum=0;
+	for(int k=0;k<n;k++) 
+	   if(a[s[k][0]-'A']==0)
+	      return false;
+	for(int i=0;i<n-1;i++)
+	    sum=(sum+a[s[i][s[i].length()-1]-'A'])%10;
+	if(sum!=a[s[n-1][s[n-1].length()-1]-'A'])
+	    return false;
+	for(int i=0;i<n;i++)
+	    for(unsigned int j=0;j<s[i].length();j++)  
+	       x[i]=x[i]*10+a[s[i][j]-'A'];
+	for(int i=1;i<n-1;i++)
+	     x[i]+=x[i-1];
+	if(x[n-2]==x[n-1])
+	      return true;
+	 return false;
+}
+
+void set(int p)
+{
+	if(p==30) 
+	{
+	 if(check()==true)
+	      number++;
+      return;
+	}
+	if(a[p]==-1)
+	{
+	    set(p+1);
+	}
+	else 
+	{
+	    for(int i=0;i<10;i++)
+	      if(use[i]==false )
+	        {
+				use[i]=true;
+				a[p]=i;
+				set(p+1);	
+				use[i]=false;
+	         }	
+	}
+	
+			
+}
+int main()
+{
+	cin>>n;
+	for(int i=0;i<n;i++)
+	   cin>>s[i];
+	for(int i=0;i<30;i++)
+	   a[i]=-1;
+	 for(int i=0;i<n;i++)
+	   for(unsigned int j=0;j<s[i].length();j++)
+	     a[s[i][j]-'A']=0;
+	  for(int i=0;i<30;i++)
+	     if(a[i]!=-1)
+	      {
+			  temp=i;
+			   break;
+		  }
+	  set(temp);
+	  cout << number << endl;
+	  return 0;
+}