import std.stdio,
       std.conv,
       std.string,
       std.range,
       std.math,
       std.algorithm;

void main()
{
    auto N = readln.strip.to!int;
    auto A = readln.split.to!(int[]);

    int[int] table;
    A.each!(a => table[a]++);
    table.values.count!"a==1".writeln;
}