#include <bits/stdc++.h>

#define llong long long

#define pb push_back
#define mp make_pair

const int INF = (int) 5e8 + 3;
const int MXN = (int) 1e6 + 7;

using namespace std;

int n, x, y;
int f[MXN], rev[MXN];

int binpow(int a, int b) {
    int res = 1;
    while (b) {
        if (b & 1)
            res = (res * 1LL * a) % INF;

        a = (1LL * a * a) % INF;
        b >>= 1;
    }
    return res;
}

int calc(int a, int b) {
    if (b > a) return 0;
    int res = f[a];
    res = (res * 1LL * rev[b]) % INF;
    res = (res * 1LL * rev[a - b]) % INF;
    return res;
}

int main() {
    f[0] = rev[0] = 1;
    for (int i = 1; i < MXN; i++) {
        f[i] = (f[i - 1] * 1LL * i) % INF;
        rev[i] = binpow(f[i], INF - 2);
    }
    scanf("%d%d%d", &n, &x, &y);
    if (x < 0) x = -x;
    if (y < 0) y = -y;

    int ans = 0;
    for (int h = x; h <= n; h += 2) {
        int v = n - h;
        if (v < y || (v - y) % 2 == 1 || h + v != n) continue;
        int cur = (1LL * calc(h, (h - x) / 2) * calc(v, (v - y) / 2)) % INF;
            cur = (1LL * cur * calc(n, h)) % INF;

        ans += cur % INF;
        if (ans >= INF) ans -= INF;
    }
    printf("%d", ans);
    return 0;
}