Problem: Bob got a job as a system administrator in X corporation. His first task was to connect n servers with the help of m two-way direct connection so that it becomes possible to transmit data from one server to any other server via these connections. Each direct connection has to link two different servers, each pair of servers should have at most one direct connection. Y corporation, a business rival of X corporation, made Bob an offer that he couldn't refuse: Bob was asked to connect the servers in such a way, that when server with index v fails, the transmission of data between some other two servers becomes impossible, i.e. the system stops being connected. Help Bob connect the servers.

Input

The first input line contains 3 space-separated integer numbers n, m, v (3 ≤ n ≤ 105, 0 ≤ m ≤ 105, 1 ≤ v ≤ n), n — amount of servers, m — amount of direct connections, v — index of the server that fails and leads to the failure of the whole system.

Output

If it is impossible to connect the servers in the required way, output -1. Otherwise output m lines with 2 numbers each — description of all the direct connections in the system. Each direct connection is described by two numbers — indexes of two servers, linked by this direct connection. The servers are numbered from 1. If the answer is not unique, output any.

Examples

Input

5 6 3


Output

1 2
2 3
3 4
4 5
1 3
3 5


Input

6 100 1


Output

-1

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
typedef long long int64;
typedef unsigned long long uint64;
const double pi = acos(-1.0);
const double eps = 1e-11;
template <class T>
inline void checkmin(T &a, T b) {
  if (b < a) a = b;
}
template <class T>
inline void checkmax(T &a, T b) {
  if (b > a) a = b;
}
template <class T>
inline T sqr(T x) {
  return x * x;
}
typedef pair<int, int> ipair;
template <class T>
inline T lowbit(T n) {
  return (n ^ (n - 1)) & n;
}
template <class T>
inline int countbit(T n) {
  return (n == 0) ? 0 : (1 + countbit(n & (n - 1)));
}
template <class T>
inline T gcd(T a, T b) {
  if (a < 0) return gcd(-a, b);
  if (b < 0) return gcd(a, -b);
  return (b == 0) ? a : gcd(b, a % b);
}
template <class T>
inline T lcm(T a, T b) {
  if (a < 0) return lcm(-a, b);
  if (b < 0) return lcm(a, -b);
  return a * (b / gcd(a, b));
}
template <class T>
inline T euclide(T a, T b, T &x, T &y) {
  if (a < 0) {
    T d = euclide(-a, b, x, y);
    x = -x;
    return d;
  }
  if (b < 0) {
    T d = euclide(a, -b, x, y);
    y = -y;
    return d;
  }
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  } else {
    T d = euclide(b, a % b, x, y);
    T t = x;
    x = y;
    y = t - (a / b) * y;
    return d;
  }
}
template <class T>
inline vector<pair<T, int> > factorize(T n) {
  vector<pair<T, int> > R;
  for (T i = 2; n > 1;) {
    if (n % i == 0) {
      int C = 0;
      for (; n % i == 0; C++, n /= i)
        ;
      R.push_back(make_pair(i, C));
    }
    i++;
    if (i > n / i) i = n;
  }
  if (n > 1) R.push_back(make_pair(n, 1));
  return R;
}
template <class T>
inline bool isPrimeNumber(T n) {
  if (n <= 1) return false;
  for (T i = 2; i * i <= n; i++)
    if (n % i == 0) return false;
  return true;
}
template <class T>
inline T eularFunction(T n) {
  vector<pair<T, int> > R = factorize(n);
  T r = n;
  for (int i = 0; i < R.size(); i++) r = r / R[i].first * (R[i].first - 1);
  return r;
}
const int MaxMatrixSize = 40;
template <class T>
inline void showMatrix(int n, T A[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) cout << A[i][j];
    cout << endl;
  }
}
template <class T>
inline T checkMod(T n, T m) {
  return (n % m + m) % m;
}
template <class T>
inline void identityMatrix(int n, T A[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) A[i][j] = (i == j) ? 1 : 0;
}
template <class T>
inline void addMatrix(int n, T C[MaxMatrixSize][MaxMatrixSize],
                      T A[MaxMatrixSize][MaxMatrixSize],
                      T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = A[i][j] + B[i][j];
}
template <class T>
inline void subMatrix(int n, T C[MaxMatrixSize][MaxMatrixSize],
                      T A[MaxMatrixSize][MaxMatrixSize],
                      T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = A[i][j] - B[i][j];
}
template <class T>
inline void mulMatrix(int n, T C[MaxMatrixSize][MaxMatrixSize],
                      T _A[MaxMatrixSize][MaxMatrixSize],
                      T _B[MaxMatrixSize][MaxMatrixSize]) {
  T A[MaxMatrixSize][MaxMatrixSize], B[MaxMatrixSize][MaxMatrixSize];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      A[i][j] = _A[i][j], B[i][j] = _B[i][j], C[i][j] = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      for (int k = 0; k < n; k++) C[i][j] += A[i][k] * B[k][j];
}
template <class T>
inline void addModMatrix(int n, T m, T C[MaxMatrixSize][MaxMatrixSize],
                         T A[MaxMatrixSize][MaxMatrixSize],
                         T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = checkMod(A[i][j] + B[i][j], m);
}
template <class T>
inline void subModMatrix(int n, T m, T C[MaxMatrixSize][MaxMatrixSize],
                         T A[MaxMatrixSize][MaxMatrixSize],
                         T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = checkMod(A[i][j] - B[i][j], m);
}
template <class T>
inline T multiplyMod(T a, T b, T m) {
  return (T)((((int64)(a) * (int64)(b) % (int64)(m)) + (int64)(m)) %
             (int64)(m));
}
template <class T>
inline void mulModMatrix(int n, T m, T C[MaxMatrixSize][MaxMatrixSize],
                         T _A[MaxMatrixSize][MaxMatrixSize],
                         T _B[MaxMatrixSize][MaxMatrixSize]) {
  T A[MaxMatrixSize][MaxMatrixSize], B[MaxMatrixSize][MaxMatrixSize];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      A[i][j] = _A[i][j], B[i][j] = _B[i][j], C[i][j] = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      for (int k = 0; k < n; k++)
        C[i][j] = (C[i][j] + multiplyMod(A[i][k], B[k][j], m)) % m;
}
template <class T>
inline T powerMod(T p, int e, T m) {
  if (e == 0)
    return 1 % m;
  else if (e % 2 == 0) {
    T t = powerMod(p, e / 2, m);
    return multiplyMod(t, t, m);
  } else
    return multiplyMod(powerMod(p, e - 1, m), p, m);
}
double dist(double x1, double y1, double x2, double y2) {
  return sqrt(sqr(x1 - x2) + sqr(y1 - y2));
}
double distR(double x1, double y1, double x2, double y2) {
  return sqr(x1 - x2) + sqr(y1 - y2);
}
template <class T>
T cross(T x0, T y0, T x1, T y1, T x2, T y2) {
  return (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0);
}
int crossOper(double x0, double y0, double x1, double y1, double x2,
              double y2) {
  double t = (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0);
  if (fabs(t) <= eps) return 0;
  return (t < 0) ? -1 : 1;
}
bool isIntersect(double x1, double y1, double x2, double y2, double x3,
                 double y3, double x4, double y4) {
  return crossOper(x1, y1, x2, y2, x3, y3) * crossOper(x1, y1, x2, y2, x4, y4) <
             0 &&
         crossOper(x3, y3, x4, y4, x1, y1) * crossOper(x3, y3, x4, y4, x2, y2) <
             0;
}
bool isMiddle(double s, double m, double t) {
  return fabs(s - m) <= eps || fabs(t - m) <= eps || (s < m) != (t < m);
}
bool isUpperCase(char c) { return c >= 'A' && c <= 'Z'; }
bool isLowerCase(char c) { return c >= 'a' && c <= 'z'; }
bool isLetter(char c) { return c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z'; }
bool isDigit(char c) { return c >= '0' && c <= '9'; }
char toLowerCase(char c) { return (isUpperCase(c)) ? (c + 32) : c; }
char toUpperCase(char c) { return (isLowerCase(c)) ? (c - 32) : c; }
template <class T>
string toString(T n) {
  ostringstream ost;
  ost << n;
  ost.flush();
  return ost.str();
}
int toInt(string s) {
  int r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
int64 toInt64(string s) {
  int64 r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
double toDouble(string s) {
  double r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
template <class T>
void stoa(string s, int &n, T A[]) {
  n = 0;
  istringstream sin(s);
  for (T v; sin >> v; A[n++] = v)
    ;
}
template <class T>
void atos(int n, T A[], string &s) {
  ostringstream sout;
  for (int i = 0; i < n; i++) {
    if (i > 0) sout << ' ';
    sout << A[i];
  }
  s = sout.str();
}
template <class T>
void atov(int n, T A[], vector<T> &vi) {
  vi.clear();
  for (int i = 0; i < n; i++) vi.push_back(A[i]);
}
template <class T>
void vtoa(vector<T> vi, int &n, T A[]) {
  n = vi.size();
  for (int i = 0; i < n; i++) A[i] = vi[i];
}
template <class T>
void stov(string s, vector<T> &vi) {
  vi.clear();
  istringstream sin(s);
  for (T v; sin >> v; vi.push_bakc(v))
    ;
}
template <class T>
void vtos(vector<T> vi, string &s) {
  ostringstream sout;
  for (int i = 0; i < vi.size(); i++) {
    if (i > 0) sout << ' ';
    sout << vi[i];
  }
  s = sout.str();
}
template <class T>
struct Fraction {
  T a, b;
  Fraction(T a = 0, T b = 1);
  string toString();
};
template <class T>
Fraction<T>::Fraction(T a, T b) {
  T d = gcd(a, b);
  a /= d;
  b /= d;
  if (b < 0) a = -a, b = -b;
  this->a = a;
  this->b = b;
}
template <class T>
string Fraction<T>::toString() {
  ostringstream sout;
  sout << a << "/" << b;
  return sout.str();
}
template <class T>
Fraction<T> operator+(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.b + q.a * p.b, p.b * q.b);
}
template <class T>
Fraction<T> operator-(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.b - q.a * p.b, p.b * q.b);
}
template <class T>
Fraction<T> operator*(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.a, p.b * q.b);
}
template <class T>
Fraction<T> operator/(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.b, p.b * q.a);
}
int n, m, v;
struct node {
  int x, y;
};
node a[100005];
int main() {
  while (scanf("%d%d%d", &n, &m, &v) != EOF) {
    memset(a, 0, sizeof(a));
    if ((m < n - 1) || ((m - n + 1) > (n - 2) * (n - 3) / 2)) {
      printf("-1\n");
      continue;
    } else {
      int count = 0;
      for (int flag = 1; flag <= n; flag++) {
        if (count >= m) break;
        if (flag != v) {
          a[count].x = v;
          a[count].y = flag;
          count++;
        }
      }
      if (v != n) {
        for (int flag = 1; flag < n; flag++) {
          for (int flag1 = flag + 1; flag1 < n; flag1++) {
            if (count >= m) goto end;
            if (flag == v || flag1 == v) continue;
            a[count].x = flag;
            a[count].y = flag1;
            count++;
          }
        }
      } else {
        for (int flag = 1; flag < n - 1; flag++) {
          for (int flag1 = flag + 1; flag1 < n - 1; flag1++) {
            if (count >= m) goto end;
            if (flag == v || flag1 == v) continue;
            a[count].x = flag;
            a[count].y = flag1;
            count++;
          }
        }
      }
    end:
      for (int flag = 0; flag < count; flag++) {
        printf("%d %d\n", a[flag].x, a[flag].y);
      }
    }
  }
}