import core.bitop;
import std.algorithm;
import std.ascii;
import std.bigint;
import std.conv;
import std.functional;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.random;
import std.typecons;
import std.container;

alias sread = () => readln.chomp();
alias Point2 = Tuple!(long, "y", long, "x");

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

void main()
{
    long n, m, x;
    scan(n, m, x);
    long[] a = new long[114 /*514*/ ];
    auto admission = aryread();
    foreach (e; admission)
    {
        a[e] = 1;
    }

    auto cost_to_n = sum(a[x .. n]);
    auto cost_to_zero = sum(a[0 .. x]);
    min(cost_to_n, cost_to_zero).writeln();
}