help please
code:
int main()
{
    int n1,n2,n3,s;
    int k1[1000],k2[1000],k3[1000];
    s=0;
        cin >> n1;
        for (int i=1;i<=n1;i++)
            cin >> k1[i];
        cin >> n2;
        for (int i=1;i<=n2;i++)
            cin >> k2[i];
        cin >> n3;
        for (int i=1;i<=n3;i++)
            cin >> k3[i];

        for (int i=1;i<=n1;i++)
            for (int j=1;j<=n2;j++)
                if (k1[i]==k2[j]) { for (int z=1;z<=n3;z++) {if (k3[z]==k2[j]) {s++; break;} } break;}
        cout << s;
}

The number of eigen values might be up to 4000. So increase your array size from 1000 to 4000.