Parity

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <climits>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <vector>
#include <list>
#define rep(i,m,n) for(i=m;i<=n;i++)
#define rsp(it,s) for(set<int>::iterator it=s.begin();it!=s.end();it++)
#define mod 1000000007
#define inf 0x3f3f3f3f
#define vi vector<int>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define ll long long
#define pi acos(-1.0)
const int maxn=1e5+10;
const int dis[4][2]={{0,1},{-1,0},{0,-1},{1,0}};
using namespace std;
ll gcd(ll p,ll q){return q==0?p:gcd(q,p%q);}
ll qpow(ll p,ll q){ll f=1;while(q){if(q&1)f=f*p;p=p*p;q>>=1;}return f;}
int n,m,k,t,id,p[maxn],a[maxn],s[maxn],d[maxn],q[maxn],v[maxn];
char b[10];
int find(int x)
{
    if(x!=p[x])
    {
        int fa=find(p[x]);
        a[x]^=a[p[x]];
        p[x]=fa;
    }
    return p[x];
}
bool join(int x,int y,int z)
{
    int px=find(x),py=find(y);
    if(px!=py)
    {
        p[py]=px;
        a[py]=a[y]^a[x]^z;
        return false;
    }
    return true;
}
int main()
{
    int i,j;
    while(~scanf("%d",&t)&&t!=-1)
    {
        scanf("%d",&n);
        memset(a,0,sizeof(a));
        j=1;
        rep(i,1,n)scanf("%d%d%s",&s[i],&d[i],b),q[j++]=s[i],q[j++]=d[i],v[i]=(b[0]==‘o‘);
        sort(q+1,q+j+1);
        int num=unique(q+1,q+j+1)-q-1;
        rep(i,1,n)
        {
            s[i]=lower_bound(q+1,q+num+1,s[i])-q-2;
            d[i]=lower_bound(q+1,q+num+1,d[i])-q-1;
        }
        rep(i,0,num)p[i]=i;
        rep(i,1,n)
        {
            if(join(s[i],d[i],v[i]))
            {
                if(a[s[i]]^a[d[i]]!=v[i])break;
            }
        }
        printf("%d\n",i-1);
    }
    //system("pause");
    return 0;
}