void counterspell(Spell *spell) {    
    Fireball *foo1 = dynamic_cast<Fireball*>(spell);
    Frostbite *foo2 = dynamic_cast<Frostbite*>(spell);
    Waterbolt *foo3 = dynamic_cast<Waterbolt*>(spell);
    Thunderstorm *foo4 = dynamic_cast<Thunderstorm*>(spell);
    if(foo1 != NULL) {
        foo1->revealFirepower();
    }
    else if(foo2 != NULL) {
        foo2->revealFrostpower();
    }
    else if(foo3 != NULL) {
        foo3->revealWaterpower();
    }
    else if(foo4 != NULL) {
        foo4->revealThunderpower();
    }
    else {
        string X = spell->revealScrollName();
        string Y = SpellJournal::read();
        int m = X.size();
        int n = Y.size();
        int L[m+1][n+1];
        int i, j;
        for (i = 0; i <= m; i++) {
            for (j = 0; j <= n; j++) {
                if (i == 0 || j == 0)
                    L[i][j] = 0; 
                else if (X[i-1] == Y[j-1])
                    L[i][j] = L[i-1][j-1] + 1;
                else
                    L[i][j] = max(L[i-1][j], L[i][j-1]);
            }
        }
        cout << L[m][n] << endl;            
    }
}