#include <iostream>

 #include<cstdio>

 #include<cstring>

 #include<algorithm>

 #include<stdlib.h>

 #include<vector>

 using namespace std;

 int fa[],r[];

 int find(int x)

 {

     if(fa[x]!=x)

     fa[x] = find(fa[x]);

     return fa[x];

 }

 int main()

 {

     int i,u,v;

     int flag = ;

     for(i = ; i <=  ; i++)

     {

         fa[i] = i;

         r[i] = ;

     }

     while(cin>>u>>v)

     {

         int x = find(u),y = find(v);

         if(x!=y)

         {

             fa[x] = y;

             r[y]+=r[x]+;

         }

         else

         r[y]+=;

     }

     for(i = ; i <=  ; i++)

     {

         int x = find(i);

         if(r[i]==)

         continue;

         if(x==i)

         {

             if(r[i]%!=)

             {

                 flag = ;

                 break;

             }

         }

     }

     if(!flag)

     printf("1\n");

     else

     printf("0\n");

     return ;

 }