1 /**************************************************************
 2     Problem: 3668
 3     User: Tunix
 4     Language: C++
 5     Result: Accepted
 6     Time:340 ms
 7     Memory:2052 kb
 8 ****************************************************************/
 9  
10 //BZOJ 3668
11 #include<vector>
12 #include<cstdio>
13 #include<cstring>
14 #include<cstdlib>
15 #include<iostream>
16 #include<algorithm>
17 #define rep(i,n) for(int i=0;i<n;++i)
18 #define F(i,j,n) for(int i=j;i<=n;++i)
19 #define D(i,j,n) for(int i=j;i>=n;--i)
20 using namespace std;
21 typedef long long LL;
22 inline int getint(){
23     int r=1,v=0; char ch=getchar();
24     for(;!isdigit(ch);ch=getchar()) if (ch==‘-‘) r=-1;
25     for(; isdigit(ch);ch=getchar()) v=v*10-‘0‘+ch;
26     return r*v;
27 }
28 const int N=1e5+10;
29 /*******************template********************/
30  
31 int n,m,a[N],lim[40],op[N];
32  
33 int opt(int a,int b,int k){
34     if (k==0) return a&b;
35     if (k==1) return a|b;
36     return a^b;
37 }
38 int main(){
39 #ifndef ONLINE_JUDGE
40     freopen("3668.in","r",stdin);
41     freopen("3668.out","w",stdout);
42 #endif 
43     n=getint(); m=getint();
44     F(i,0,30) lim[i]=m>>i&1;
45     char s[5];
46     F(i,1,n){
47         scanf("%s",s); a[i]=getint();
48         if (s[0]==‘A‘) op[i]=0;
49         if (s[0]==‘O‘) op[i]=1;
50         if (s[0]==‘X‘) op[i]=2;
51     }
52     bool sign=1;
53     int ans=0;
54     D(i,30,0){
55         int now=1,tmp0=0,tmp1=1;
56         F(j,1,n)
57             tmp0=opt(tmp0,a[j]>>i&1,op[j]),
58             tmp1=opt(tmp1,a[j]>>i&1,op[j]);
59         if ((tmp0>=tmp1) || (sign && lim[i]==0)){
60             if (lim[i]==1) sign=0;
61             ans|=tmp0<<i;
62         }else ans|=tmp1<<i;
63     }
64     printf("%d\n",ans);
65     return 0;
66 }