PacMan_XI

#include <fstream>
using namespace std;

int main() /// E (i,j+1) si S-E (i+1,j+1).
{
    int n,m;
	long long int D[41][41];
    ifstream f("pacman_xi.in");
    f>>n>>m;
    f.close();
    for(int i=1;i<=n;++i)
        for(int j=1;j<=m;++j)
            if(i==1)
                D[i][j]=1;
            else
                if(j==1)
                    D[i][j]=0;
            else
                D[i][j]=D[i-1][j-1]+D[i][j-1];
    ofstream g("pacman_xi.out");
    g<<D[n][m]<<'\n';
    g.close();
    return 0;
}