#include <bits/stdc++.h>

#define ll long long

#define setIO(s) freopen(s".in","r",stdin)

using namespace std;

ll qpow[40];

int main()

{

    // setIO("input");

    ll a=0,b=0,re=0;

    int i,j,n,m;

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

    for(i=0;i<40;++i) qpow[i]=1ll<<i, a+=qpow[i];

    for(i=1;i<=n;++i)

    {

        ll x;

        char op[5];

        scanf("%s%lld",op,&x);

        if(op[0]=='A') a&=x,b&=x;

        if(op[0]=='O') a|=x,b|=x;

        if(op[0]=='X') a^=x,b^=x;

    }

    for(i=33;i>=0;--i)

    {

        if(b&qpow[i]) re+=qpow[i];

        else if(a&qpow[i] && qpow[i]<=1ll*m) re+=qpow[i], m-=(int)qpow[i];

    }

    printf("%lld\n",re);

    return 0;

}

#include <bits/stdc++.h>

#define N 100005

#define lson now<<1

#define rson now<<1|1

#define ll unsigned long long

#define setIO(s) freopen(s".in","r",stdin)

using namespace std;

int n,m;

struct node

{

    ll f0,f1;

    node operator+(const node &b)const

    {

        node a;

        a.f0=(~f0&b.f0)|(f0&b.f1);

        a.f1=(~f1&b.f0)|(f1&b.f1);

        return a;

    }

}f[N<<2],A[N];

void build(int l,int r,int now)

{

    if(l==r)

    {

        f[now]=A[l];

        return;

    }

    int mid=(l+r)>>1;

    if(l<=mid) build(l,mid,lson);

    if(r>mid)  build(mid+1,r,rson);

    f[now]=f[lson];

    if(rson) f[now]=f[now]+f[rson];

}

int main()

{

    // setIO("input");

    int i,j;

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

    for(i=1;i<=n;++i)

    {

        ll x;

        char op[5];

        scanf("%s%llu",op,&x);

        if(op[0]=='A') A[i]=(node){0,x};

        if(op[0]=='O') A[i]=(node){x,~0};

        if(op[0]=='X') A[i]=(node){x,~x};

    }

    build(1,n,1);

    ll re=0;

    for(i=32;i>=0;--i)

    {

        if(f[1].f0&(1ll<<i)) re+=(1ll<<i);

        else if((f[1].f1&(1ll<<i)) && (1ll<<i)<=1ll*m)

        {

            m-=(int)(1ll<<i);

            re+=(1ll<<i);

        }

    }

    printf("%lld\n",(long long)re);

    return 0;

}