import std.algorithm;
import std.array;
import std.conv;
import std.math;
import std.range;
import std.stdio;
import std.string;
import std.typecons;

T read(T)() { return readln.chomp.to!T; }
T[] reads(T)() { return readln.split.to!(T[]); }
alias readint = read!int;
alias readints = reads!int;

void main() {
    int n = readint;
    bool[int] d;
    for (int i = 0; i < n; i++) {
        int x = readint;
        d[x] = true;
    }

    writeln(d.keys.length);
}
