import std.stdio, std.string, std.conv;
import std.range, std.algorithm, std.array, std.typecons, std.container;
import std.math, std.numeric, core.bitop;

enum inf3 = 1_001_001_001;
enum inf6 = 1_001_001_001_001_001_001L;
enum mod = 1_000_000_007L;



void main() {
    auto c = new long[](30);
    c[0] = c[1] = 1;

    // カタラン数の漸化式
    // c[n] = c[n - 1] * c[0] + c[n - 2] * c[1] + ... + c[1] * c[n - 2] + c[0] * c[n - 1]
    foreach (i ; 2 .. 30) {
        foreach (j ; 0 .. i) {
            c[i] += c[i - 1 - j] * c[j];
        }
    }


    int n;
    scan(n);
    writeln(c[n]);
}







void scan(T...)(ref T args) {
    import std.stdio : readln;
    import std.algorithm : splitter;
    import std.conv : to;
    import std.range.primitives;

    auto line = readln().splitter();
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}

void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}