位运算每一位都是相对独立的
一般来说,需要从高位到低位每个 bit 依次检查
决定该位填 0 或者填 1
如果这一位填的是 0,那么对于这个数 $val$,该位无贡献
否则的话,应该要将
val += (1 << bit)
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <vector>
#include <stack>
#include <map>
#include <set>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <bitset>
#include <assert.h>
using namespace std;
typedef long long ll;
typedef set<int>::iterator ssii;
#define Cmp(a, b) memcmp(a, b, sizeof(b))
#define Cpy(a, b) memcpy(a, b, sizeof(b))
#define Set(a, v) memset(a, v, sizeof(a))
#define debug(x) cout << #x << ": " << x << endl
#define _forS(i, l, r) for(set<int>::iterator i = (l); i != (r); i++)
#define _rep(i, l, r) for(int i = (l); i <= (r); i++)
#define _for(i, l, r) for(int i = (l); i < (r); i++)
#define _forDown(i, l, r) for(int i = (l); i >= r; i--)
#define debug_(ch, i) printf(#ch"[%d]: %d\n", i, ch[i])
#define debug_m(mp, p) printf(#mp"[%d]: %d\n", p->first, p->second)
#define debugS(str) cout << "dbg: " << str << endl;
#define debugArr(arr, x, y) _for(i, 0, x) { _for(j, 0, y) printf("%c", arr[i][j]); printf("\n"); }
#define _forPlus(i, l, d, r) for(int i = (l); i + d < (r); i++)
#define lowbit(i) (i & (-i))
#define MPR(a, b) make_pair(a, b)
pair<int, int> crack(int n) {
int st = sqrt(n);
int fac = n / st;
while (n % st) {
st += 1;
fac = n / st;
}
return make_pair(st, fac);
}
inline ll qpow(ll a, int n) {
ll ans = 1;
for(; n; n >>= 1) {
if(n & 1) ans *= 1ll * a;
a *= a;
}
return ans;
}
template <class T>
inline bool chmax(T& a, T b) {
if(a < b) {
a = b;
return true;
}
return false;
}
ll gcd(ll a, ll b) {
return b == 0 ? a : gcd(b, a % b);
}
ll ksc(ll a, ll b, ll mod) {
ll ans = 0;
for(; b; b >>= 1) {
if (b & 1) ans = (ans + a) % mod;
a = (a * 2) % mod;
}
return ans;
}
ll ksm(ll a, ll b, ll mod) {
ll ans = 1 % mod;
a %= mod;
for(; b; b >>= 1) {
if (b & 1) ans = ksc(ans, a, mod);
a = ksc(a, a, mod);
}
return ans;
}
template <class T>
inline bool chmin(T& a, T b) {
if(a > b) {
a = b;
return true;
}
return false;
}
bool _check(int x) {
//
return true;
}
int bsearch1(int l, int r) {
while (l < r) {
int mid = (l + r) >> 1;
if(_check(mid)) r = mid;
else l = mid + 1;
}
return l;
}
int bsearch2(int l, int r) {
while (l < r) {
int mid = (l + r + 1) >> 1;
if(_check(mid)) l = mid;
else r = mid - 1;
}
return l;
}
template<class T>
bool lexSmaller(vector<T> a, vector<T> b) {
int n = a.size(), m = b.size();
int i;
for(i = 0; i < n && i < m; i++) {
if (a[i] < b[i]) return true;
else if (b[i] < a[i]) return false;
}
return (i == n && i < m);
}
// ============================================================== //
const int maxn = 1e5 + 10;
pair<string, int> a[maxn];
int n, m;
inline int calc(int bit, int cur) {
_rep(i, 1, n) {
int x = a[i].second >> bit & 1;
if (a[i].first == "AND") cur &= x;
else if (a[i].first == "OR") cur |= x;
else cur ^= x;
}
return cur;
}
void solve() {
int val = 0, ans = 0;
for (int bit = 29; bit >= 0; bit--) {
int res0 = calc(bit, 0);
int res1 = calc(bit, 1);
if (val + (1<<bit) <= m && res0 < res1) {
val += (1<<bit);
ans += (res1<<bit);
}
else ans += res0<<bit;
}
printf("%d\n", ans);
}
int main() {
//freopen("input.txt", "r", stdin);
scanf("%d%d", &n, &m);
_rep(i, 1, n) {
char str[10];
int x;
scanf("%s%d", str, &x);
a[i] = make_pair(str, x);
}
// then solve
solve();
}