**Parity game**

Now and then you play the following game with your friend. Your friend

writes down a sequence consisting of zeroes and ones. You choose a

continuous subsequence (for example the subsequence from the third to

the fifth digit inclusively) and ask him, whether this subsequence

contains even or odd number of ones. Your friend answers your question

and you can ask him about another subsequence and so on. Your task is

to guess the entire sequence of numbers.

You suspect some of your friend's answers may not be correct and you

want to convict him of falsehood. Thus you have decided to write a

program to help you in this matter. The program will receive a series

of your questions together with the answers you have received from

your friend. The aim of this program is to find the first answer which

is provably wrong, i.e. that there exists a sequence satisfying

answers to all the previous questions, but no such sequence satisfies

this answer.

Input:

The first line of input file PARITY.IN contains one number, which is

the length of the sequence of zeroes and ones. This length is less or

equal to 1000000000. In the second line, there is one positive integer

which is the number of questions asked and answers to them. The number

of questions and answers is less or equal to 5000. The remaining lines

specify questions and answers. Each line contains one question and the

answer to this question: two integers (the position of the first and

last digit in the chosen subsequence) and one word which is either

`even' or `odd' (the answer, i.e. the parity of the number of ones in

the chosen subsequence, where `even' means an even number of ones and

`odd' means an odd number).

Output:

There is only one line in output file PARITY.OUT containing one

integer X. Number X says that there exists a sequence of zeroes and

ones satisfying first X parity conditions, but there exists none

satisfying X+1 conditions. If there exists a sequence of zeroes and

ones satisfying all the given conditions, then number X should be the

number of all the questions asked.

Example 1:

PARITY.IN

10

5

1 2 even

3 4 odd

5 6 even

1 6 even

7 10 odd

PARITY.OUT

3

Example 2:

PARITY.IN

10

5

1 2 even

1 4 even

2 4 odd

1 10 even

3 10 even

PARITY.OUT

5