import std.stdio;
import std.string;
import std.format;
import std.conv;
import std.typecons;
import std.algorithm;
import std.functional;
import std.bigint;
import std.numeric;
import std.array;
import std.math;
import std.range;
import std.container;
import std.concurrency;
import std.traits;
import std.uni;
import std.regex;
import core.bitop : popcnt;
alias Generator = std.concurrency.Generator;

enum long INF = long.max/5;

void main() {
  long N;
  scanln(N);
  struct P {
    long a, b;
  }
  P[] ps = new P[N];
  foreach(i; 0..N) scanln(ps[i]);
  ps.sort!"a.a != b.a ? a.a < b.a : a.b < b.b";

  if (N%2 != 0) {
    long left, right;
    {
      long l = 0;
      long r = 1000000010L;
      while(r - l > 1) {
        long c = (l + r)/2;
        long t = 0;
        foreach(i; 0..N) {
          if (ps[i].a <= c) t++;
        }
        if (t >= (N + 1)/2) {
          r = c;
        } else {
          l = c;
        }
      }
      left = r;
    }
    {
      long l = 0;
      long r = 1000000010L;
      while(r - l > 1) {
        long c = (l + r)/2;
        long t = 0;
        foreach(i; 0..N) {
          if (ps[i].b >= c) t++;
        }
        if (t >= (N + 1)/2) {
          l = c;
        } else {
          r = c;
        }
      }
      right = l;
    }
    writeln(max(0, right - left + 1));
  } else {
    long left, right;
    {
      long l = 0;
      long r = 2*1000000010L;
      while(r - l > 1) {
        long c = (l + r)/2;
        long t = 0;
        foreach(i; 0..N) {
          if (c%2 == 0) {
            if (ps[i].a <= c/2) t++;
          } else {
            if (ps[i].a <= c*0.5) t++;
          }
        }
        if (t >= N/2+1) {
          r = c;
        } else {
          l = c;
        }
      }
      left = r;
    }
    {
      long l = 0;
      long r = 2*1000000010L;
      while(r - l > 1) {
        long c = (l + r)/2;
        long t = 0;
        foreach(i; 0..N) {
          if (c%2 == 0) {
            if (ps[i].b >= c/2) t++;
          } else {
            if (ps[i].b >= c*0.5) t++;
          }
        }
        if (t >= N/2+1) {
          l = c;
        } else {
          r = c;
        }
      }
      right = l;
    }

    long left2, right2;
    {
      long l = 0;
      long r = 2*1000000010L;
      while(r - l > 1) {
        long c = (l + r)/2;
        long t = 0;
        foreach(i; 0..N) {
          if (c%2 == 0) {
            if (ps[i].a <= c/2) t++;
          } else {
            if (ps[i].a <= c*0.5) t++;
          }
        }
        if (t >= N/2) {
          r = c;
        } else {
          l = c;
        }
      }
      left2 = r;
    }
    {
      long l = 0;
      long r = 2*1000000010L;
      while(r - l > 1) {
        long c = (l + r)/2;
        long t = 0;
        foreach(i; 0..N) {
          if (c%2 == 0) {
            if (ps[i].b >= c/2) t++;
          } else {
            if (ps[i].b >= c*0.5) t++;
          }
        }
        if (t >= N/2) {
          l = c;
        } else {
          r = c;
        }
      }
      right2 = l;
    }
    writeln(max(0, (right+right2)/2 - (left+left2)/2 + 1));
  }
}


// ----------------------------------------------


void times(alias fun)(long n) {
  // n.iota.each!(i => fun());
  foreach(i; 0..n) fun();
}
auto rep(alias fun, T = typeof(fun()))(long n) {
  // return n.iota.map!(i => fun()).array;
  T[] res = new T[n];
  foreach(ref e; res) e = fun();
  return res;
}

T ceil(T)(T x, T y) if (isIntegral!T || is(T == BigInt)) {
  // `(x+y-1)/y` will only work for positive numbers ...
  T t = x / y;
  if (y > 0 && t * y < x) t++;
  if (y < 0 && t * y > x) t++;
  return t;
}

T floor(T)(T x, T y) if (isIntegral!T || is(T == BigInt)) {
  T t = x / y;
  if (y > 0 && t * y > x) t--;
  if (y < 0 && t * y < x) t--;
  return t;
}

ref T ch(alias fun, T, S...)(ref T lhs, S rhs) {
  return lhs = fun(lhs, rhs);
}
unittest {
  long x = 1000;
  x.ch!min(2000);
  assert(x == 1000);
  x.ch!min(3, 2, 1);
  assert(x == 1);
  x.ch!max(100).ch!min(1000); // clamp
  assert(x == 100);
  x.ch!max(0).ch!min(10); // clamp
  assert(x == 10);
}

mixin template Constructor() {
  import std.traits : FieldNameTuple;
  this(Args...)(Args args) {
    // static foreach(i, v; args) {
    foreach(i, v; args) {
      mixin("this." ~ FieldNameTuple!(typeof(this))[i]) = v;
    }
  }
}

template scanln(Args...) {
  enum sep = " ";

  enum n = (){
    long n = 0;
    foreach(Arg; Args) {
      static if (is(Arg == class) || is(Arg == struct) || is(Arg == union)) {
        n += Fields!Arg.length;
      } else {
        n++;
      }
    }
    return n;
  }();

  enum fmt = n.rep!(()=>"%s").join(sep);

  enum argsString = (){
    string[] xs = [];
    foreach(i, Arg; Args) {
      static if (is(Arg == class) || is(Arg == struct) || is(Arg == union)) {
        foreach(T; FieldNameTuple!Arg) {
          xs ~= "&args[%d].%s".format(i, T);
        }
      } else {
        xs ~= "&args[%d]".format(i);
      }
    }
    return xs.join(", ");
  }();

  void scanln(auto ref Args args) {
    string line = readln.chomp;
    static if (__VERSION__ >= 2074) {
      mixin(
        "line.formattedRead!fmt(%s);".format(argsString)
      );
    } else {
      mixin(
        "line.formattedRead(fmt, %s);".format(argsString)
      );
    }
  }
}

// fold was added in D 2.071.0
static if (__VERSION__ < 2071) {
  template fold(fun...) if (fun.length >= 1) {
    auto fold(R, S...)(R r, S seed) {
      static if (S.length < 2) {
        return reduce!fun(seed, r);
      } else {
        return reduce!fun(tuple(seed), r);
      }
    }
  }
}

// popcnt with ulongs was added in D 2.071.0
static if (__VERSION__ < 2071) {
  ulong popcnt(ulong x) {
    x = (x & 0x5555555555555555L) + (x>> 1 & 0x5555555555555555L);
    x = (x & 0x3333333333333333L) + (x>> 2 & 0x3333333333333333L);
    x = (x & 0x0f0f0f0f0f0f0f0fL) + (x>> 4 & 0x0f0f0f0f0f0f0f0fL);
    x = (x & 0x00ff00ff00ff00ffL) + (x>> 8 & 0x00ff00ff00ff00ffL);
    x = (x & 0x0000ffff0000ffffL) + (x>>16 & 0x0000ffff0000ffffL);
    x = (x & 0x00000000ffffffffL) + (x>>32 & 0x00000000ffffffffL);
    return x;
  }
}


Measured memory_bytes: 7052