#include "Ali.h"
#include <bits/stdc++.h>
using namespace std;
#define REP(i, j, k) for (int i = j; i < k; i++)
#define RREP(i, j, k) for (int i = j; i >= k; i--)
template <class T>
bool mnto(T &a, const T b) {return a > b ? a = b, 1 : 0;}
template <class T>
bool mxto(T &a, const T b) {return a < b ? a = b, 1 : 0;}
typedef long long ll;
#define FI first
#define SE second
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
#define ALL(x) x.begin(), x.end()
#define SZ(x) (int) x.size()
#define pb push_back
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<ll> vll;
#ifndef DEBUG
#define cerr if(0) cerr
#endif
namespace {
const int MAXN = 150005;
const int INF = 1000000005;
const ll LINF = 1000000000000000005;
int n;
vi adj[MAXN];
int rt;
int pre[MAXN], pst[MAXN], mppre[MAXN], p[MAXN], ptr;
void dfs(int u, int cp) {
p[u] = cp;
pre[u] = ptr++;
mppre[pre[u]] = u;
for (int v : adj[u]) {
if (v == cp) continue;
dfs(v, u);
}
pst[u] = ptr;
}
}
void Init(int N, vi U, vi V) {
n = N;
REP (i, 0, n) {
adj[i].clear();
}
REP (i, 0, n - 1) {
adj[U[i]].pb(V[i]);
adj[V[i]].pb(U[i]);
}
ptr = 0;
REP (i, 0, n) {
if (adj[i].size() == 1) {
rt = i;
dfs(i, -1);
break;
}
}
REP (i, 0, n) {
SetID(i, pre[i]);
}
}
string SendA(string S) {
string res = "";
REP (i, 1, n) {
int u = mppre[i - 1], v = mppre[i];
while (pst[u] <= pre[v]) {
u = p[u];
res += '0';
}
res += '1';
}
return res;
}
#include "Benjamin.h"
#include <bits/stdc++.h>
using namespace std;
#define REP(i, j, k) for (int i = j; i < k; i++)
#define RREP(i, j, k) for (int i = j; i >= k; i--)
template <class T>
bool mnto(T &a, const T b) {return a > b ? a = b, 1 : 0;}
template <class T>
bool mxto(T &a, const T b) {return a < b ? a = b, 1 : 0;}
typedef long long ll;
#define FI first
#define SE second
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
#define ALL(x) x.begin(), x.end()
#define SZ(x) (int) x.size()
#define pb push_back
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<ll> vll;
#ifndef DEBUG
#define cerr if(0) cerr
#endif
namespace {
const int MAXN = 150005;
const int INF = 1000000005;
const ll LINF = 1000000000000000005;
int n, x, y;
vi adj[MAXN];
int p[MAXN], ptr;
int dis[MAXN];
void dfs(int u, int p) {
for (int v : adj[u]) {
if (v == p) continue;
dis[v] = dis[u] + 1;
dfs(v, u);
}
}
}
string SendB(int N, int X, int Y) {
n = N; x = X; y = Y;
string s(20, '0');
return s;
}
int Answer(string T) {
REP (i, 0, n) {
adj[i].clear();
dis[i] = 0;
}
int u = 0;
int ptr = 1;
for (char c : T) {
if (c == '1') {
p[ptr] = u;
adj[u].pb(ptr);
adj[ptr].pb(u);
u = ptr++;
} else {
u = p[u];
}
}
dfs(x, -1);
return dis[y];
}
