function P = matchproc(N0)
global m n N
N = N0;

m = 2;
n = N^2;

P = zeros(m^n,1);
for xi=1:m^n
  x = i2c(xi);
  b = goodmatch(x);
  P(xi) = b;
end
P = P/sum(P);

return

function b = goodmatch(x)
global m n N
U = []; V = [];
b = 1;
for i=1:n
  if x(i)
    uv = ind2coord(i,[N N]);
    u = uv(1);
    v = uv(2);
    if (ismember(u,U) | ismember(v,V))
      b = 0;
      return
    end
    U(end+1) = u;
    V(end+1) = v;
  end
end
b = (length(U)==N)*(length(V)==N);
return