1 #include <iostream>
  2 #include<cstdio>
  3 #include<cstring>
  4 #include<algorithm>
  5 #include<cstdlib>
  6 #include<map>
  7 using namespace std;
  8 #define N 10010
  9 map<int,int>q;//map进行离散化
 10 int que[N];
 11 struct node
 12 {
 13     int l,r,d;
 14 }p[N];
 15 int father[N<<1];
 16 int find(int x)
 17 {
 18     if(father[x]!=x)
 19     {
 20         father[x] = find(father[x]);
 21     }
 22     return father[x];
 23 }
 24 void union1(int x,int y)
 25 {
 26     int tx = find(x);
 27     int ty = find(y);
 28     if(tx!=ty)
 29     father[tx] = ty;
 30 }
 31 int main()
 32 {
 33     int i,k,n,g=0;
 34     char cc[10];
 35     while(scanf("%d",&n)!=EOF)
 36     {
 37         if(n==-1)
 38         break;
 39         q.clear();
 40         g = 0;
 41         scanf("%d",&k);
 42         for(i = 1; i <= k ; i++)
 43         {
 44             scanf("%d%d%s",&p[i].l,&p[i].r,cc);
 45             if(strcmp(cc,"even")==0)
 46             p[i].d = 0;
 47             else
 48             p[i].d = 1;
 49             que[g++] = p[i].l;
 50             que[g++] = p[i].r;
 51         }
 52         sort(que,que+g);
 53         int o = 1;
 54         q[que[0]] = o;
 55         for(i = 1 ; i < g ; i++)
 56         {
 57             if(que[i]!=que[i-1])
 58             {
 59                 o++;
 60                 q[que[i]] = o;
 61             }
 62         }
 63         for(i = 1; i <= o+N ; i++)
 64             father[i] = i;
 65         for(i = 1; i <= k ; i++)
 66         {
 67             int tx = q[p[i].l]-1;
 68             int ty = q[p[i].r];
 69             if(p[i].d)
 70             {
 71                 if(find(tx)==find(ty))
 72                 {
 73                     printf("%d\n",i-1);
 74                     break;
 75                 }
 76                 else
 77                 {
 78                     union1(tx,ty+N);//敌人的敌人是朋友
 79                     union1(tx+N,ty);
 80                 }
 81             }
 82             else
 83             {
 84                 if(find(tx)==find(ty+N))
 85                 {
 86                     printf("%d\n",i-1);
 87                     break;
 88                 }
 89                 else
 90                 {
 91                     union1(tx,ty);//朋友的朋友是朋友
 92                     union1(tx+N,ty+N);
 93                 }
 94             }
 95         }
 96         if(i==k+1)
 97         printf("%d\n",k);
 98     }
 99     return 0;
100 }