#include <bits/stdc++.h>
using namespace std;

int main() 

{
    int n,x,y; cin>>n>>x>>y;
    int f[n][n];
    f[0][0]=1;
    f[1][0]=1;
    f[0][1]=1;
    f[1][1]=2;   

    for(int i = 2; i <= x; i ++ ) {
        f[i][0] = f[i-1][0] + f[i-2][0];
    }
    for(int i = 2; i <= x; i ++ ) {
        f[i][1] = f[i-1][1] + f[i-2][1] + f[i][0];
    }
    for(int j = 2; j <= y; j ++ ) {
        f[0][j] = f[0][j-1] + f[0][j-2];
    }
    for(int j = 2; j <= y; j ++ ) {
        f[1][j] = f[1][j-1] + f[1][j-2] + f[0][j];
    }

    for (int i=2; i<=x; i++)
        for (int j=2; j<=y; j++) {
            f[i][j]=f[i-1][j]+f[i-2][j]+f[i][j-1]+f[i][j-2];
            // cout << i << " " << j << " " << f[i][j] << endl;
        }

    cout<< f[x][y];

    return 0;
}