Solve the programming task below in a Python markdown code block.
Kundu is true tree lover. Tree is a connected graph having N vertices and N-1  edges. Today when he got a tree, he colored each edge with one of either red(r) or black(b) color. He is interested in knowing how many triplets(a,b,c) of vertices are there , such that, there is atleast one edge having red color on all the three paths i.e. from vertex a to b, vertex b to c and vertex c to a . Note that (a,b,c), (b,a,c) and all such permutations will be considered as the same triplet. 

If the answer is greater than $10^{9}$ + 7, print the answer modulo (%) $10^{9}$ + 7.

Input Format 

The first line contains an integer N, i.e., the number of vertices in tree. 

The next N-1 lines represent edges:  2 space separated integers denoting an edge followed by a color of the edge. A color of an edge is denoted by a small letter of English alphabet, and it can be either red(r) or black(b).  

Output Format 

Print a single number i.e. the number of triplets.  

Constraints 

1 ≤ N ≤ $10^{5}$
 
A node is numbered between 1 to N.  

Sample Input  

5
1 2 b
2 3 r
3 4 r
4 5 b

Sample Output  

4

Explanation

Given tree is something like this.

(2,3,4) is one such triplet because on all paths i.e 2 to 3, 3 to 4 and 2 to 4 there is atleast one edge having red color.

(2,3,5), (1,3,4) and (1,3,5) are other such triplets. 

Note that (1,2,3) is NOT a triplet, because the path from 1 to 2 does not have an edge with red color.