#include<stdio.h>

#define NMAX 252

int n;
int v[NMAX][NMAX];

inline void swap(int a, int b)
{
    int aux;
    for(int j=1; j<=n; ++j)
    {
        aux=v[a][j];
        v[a][j]=v[b][j];
        v[b][j]=aux;
    }
    aux=v[a][n+1];
    v[a][n+1]=v[b][n+1];
    v[b][n+1]=aux;
}

inline void elim(int a, int b)
{
    for(int j=1; j<=n; ++j)
        v[a][j]^=v[b][j];
    v[a][n+1]^=v[b][n+1];
}

bool Gauss()
{
    int x;
    for(int i=1, j=1; i<=n; ++i, ++j)
    {
        x=i;
        while(!v[i][x])++x;

        if(x>n)
            return false;

        if(x!=i)
            swap(i, x);

        for(x=1; x<=n; ++x)
            if(v[x][j] && x!=i)
                elim(x, i);
    }

    return true;
}

int main()
{
    freopen("date.in", "r", stdin);
    freopen("date.out", "w", stdout);

    int x;

    scanf("%d", &n);

    for(int i=1; i<=n; ++i)
    {
        while(true)
        {
            scanf("%d", &x);

            if(x==-1)
                break;

            v[i][x]=1;
        }
        v[i][n+1]=1;
    }

    if(Gauss())
    {
        for(int i=1; i<=n; ++i)
            if(v[i][n+1])
                printf("%d ", i);
        printf("\n");
    }
    else
        printf("No solution\n");
    return 0;
}