#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define ls (p<<1)
#define rs (p<<1|1)
#define mid ((l+r)>>1)
#define lb(x) (x&-x)

const int maxn=100010;
const int mo=1000000007;
const int inf=0x7f7f7f7f7f7f7f7f;

inline int read(){
	int x=0,f=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){
		if(ch=='-')
			f=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9'){
		x=x*10+ch-'0';
		ch=getchar();
	}
	return x*f;
}

int n,m,t[maxn],ans,ans0,cnt0,cnt1=-1;

string op[maxn];

signed main(){
	n=read();
	m=read();
	for(int i=1;i<=n;i++){
		cin>>op[i];
		t[i]=read();
		if(op[i][0]=='A'){
			cnt0&=t[i];
			cnt1&=t[i];
		}
		else if(op[i][0]=='O'){
			cnt0|=t[i];
			cnt1|=t[i];
		}
		else{
			cnt0^=t[i];
			cnt1^=t[i];			
		}
	}
	int is=1;
	for(int i=50;i>=0;i--){
		bool c0=(cnt0>>i)&1,c1=(cnt1>>i)&1,lim=(m>>i)&1;
		if(c0|(c1&lim)|(c1&(!is)))
			ans+=1ll<<i;		
		if(c0&lim)
			is=0;
			
	}
	printf("%lld\n",ans);
	return 0;
}