def lcs_of_three(X, Y, Z, m, n, o): 
	L = [[[0 for i in range(o+1)] for j in range(n+1)] 
		for k in range(m+1)] 
	for i in range(m+1): 
		for j in range(n+1): 
			for k in range(o+1): 
				if (i == 0 or j == 0 or k == 0): 
					L[i][j][k] = 0
				elif (X[i-1] == Y[j-1] and
					X[i-1] == Z[k-1]): 
					L[i][j][k] = L[i-1][j-1][k-1] + 1
				else: 
					L[i][j][k] = max(max(L[i-1][j][k], 
					L[i][j-1][k]), 
									L[i][j][k-1]) 
	return L[m][n][o]