#include <algorithm>

#include <bitset>

#include <cctype>

#include <cerrno>

#include <clocale>

#include <cmath>

#include <complex>

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <ctime>

#include <deque>

#include <exception>

#include <fstream>

#include <functional>

#include <limits>

#include <list>

#include <map>

#include <iomanip>

#include <ios>

#include <iosfwd>

#include <iostream>

#include <istream>

#include <ostream>

#include <queue>

#include <set>

#include <sstream>

#include <stdexcept>

#include <streambuf>

#include <string>

#include <utility>

#include <vector>

#include <cwchar>

#include <cwctype>

#include <stack>

#include <limits.h>

using namespace std;

struct Query

{

        int l,r,op;

} q[];

int k,n,i,x,y,len;

int l[],r[],fa[],d[],a[];

char s[][];

inline int get_root(int x)

{

        if (fa[x] == x) return x;

        int f = get_root(fa[x]);

        d[x] ^= d[fa[x]];

        return fa[x] = f;

}

int main()

{

        scanf("%d%d",&k,&n);

        for (i = ; i <= n; i++)

        {

                scanf("%d%d%s",&l[i],&r[i],&s[i]);

                a[++len] = l[i] - ;

                a[++len] = r[i];

        }

        sort(a+,a+len+);

        len = unique(a+,a+len+) - a - ;

        for (i = ; i <= n; i++)

        {

                q[i].l = lower_bound(a+,a+len+,l[i]-) - a;

                q[i].r = lower_bound(a+,a+len+,r[i]) - a;

                q[i].op = strcmp(s[i],"odd") ==  ?  : ;

        }

        for (i = ; i <=  * n; i++) fa[i] = i;

        for (i = ; i <= n; i++)

        {

                x = get_root(q[i].l);

                y = get_root(q[i].r);

                if (x == y)

                {

                        if ((d[q[i].l] ^ d[q[i].r]) != q[i].op)

                        {

                                printf("%d\n",i-);

                                exit();

                        }

                  }    else

                 {

                         fa[x] = y;

                         d[x] = d[q[i].l] ^ d[q[i].r] ^ q[i].op;

                 }

        }

        printf("%d\n",n);

        return ;

}