#include<bits/stdc++.h>

 using namespace std;

 const int maxn = ;

 int n,m;

 int a[maxn],b[maxn];

 void work(){

     int z = ;

     for(int i=;i>=;i--){

     if((<<i)+z > m)continue;

     int l = (<<i),r=;

     for(int i=;i<=n;i++){

         if(a[i] == ) l = (l&b[i]),r = (r&b[i]);

         else if(a[i] == ) l = (l|b[i]),r = (r|b[i]);

         else l = (l^b[i]),r = (r^b[i]);

     }

     if((r&(<<i)) != ) continue;

     if((l&(<<i)) == ) continue;

     z += (<<i);

     }

     for(int i=;i<=n;i++){

     if(a[i] == ) z = (z&b[i]);

     else if(a[i] == ) z=  (z|b[i]);

     else z = (z^b[i]);

     }

     printf("%d\n",z);

 }

 int main(){

     scanf("%d%d",&n,&m);

     for(int i=;i<=n;i++){

     char ch = getchar();

     while(ch > 'Z' || ch < 'A') ch = getchar();

     if(ch == 'A'){a[i] = ;}

     else if(ch == 'O'){a[i] = ;}

     else a[i] = ;

     while(ch  != ' ') ch = getchar();

     scanf("%d",&b[i]);

     }

     work();

     return ;

 }