#include <cstdio>
#include <cctype>
#include <map>

struct istream{
    
    template <typename T>
    istream &operator>>(T &x){
        
        x = 0;
        char c = getchar_unlocked();
        
        while (!isdigit(c)) c = getchar_unlocked();
        while (isdigit(c)) x = x * 10 + c - '0',c = getchar_unlocked();
        
        return *this;
    }
    
}cin;

int main(){
    
    int n,q,ans = 0;
    std::map <std::pair <int,int>,int> a;
    
    cin >> n >> q;
    for (int i = 1;i <= n;i++){
        
        int s;
        
        cin >> s;
        for (int j = 1;j <= s;j++) cin >> a[std::make_pair(i,j)];
        
    }
    while (q--){
        
        int x,y;
        
        cin >> x >> y;
        ans ^= a[std::make_pair(x,y)];
        
    }
    printf("%d\n",ans);
    
    return 0;
}

注意cin已经是快读了！！！