#include <cstdio>

using namespace std;

int lst[100001], vf[200001], nr[200001], nr;

void dfs(int x)
{
    int p,y;
    viz[x] = true;
    p = lst[x];
    while(p != 0)
    {
        y = vf[p];
        if(!viz[y])
            dfs(y);
        p = urm[p];
    }
}
inline void adauga(int x, int y)
{
    nr++;
    vf[m] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}
int main()
{
    FILE *in, *out;
    in = fopen("dfs.in", "r")
    out = fopen("dfs.out", "w");
    int n, m;
    fscanf(in, "%d", &n);
    fscanf(in, "%d", &m);
    for(i = 1; i <= m; i++)
    {
        fscanf(in, "%d", &a);
        fscanf(in, "%d", &b);
        adauga(a, b);

    }
    return 0;
}