CALC_LEN_PATH(G, A, B, LEN){
	G2 = G // copy
	for t=1 to n{
		G3 = ZeroMatrix
		for k = 1 to n{
			for i = 1 to n{
				for j = 1 to n{
					if(G2[i][k]>0 and G[k][j]>0){
						G3 += G2[i][k]
					}
				}
			}
		}
		G2 = G3 //copy
	}
	return G2
}