#include <cstdio>
#include <vector>
#include <cstring>
using namespace std;
int const MAX_N=251;
int N, M;
vector<int> graph[MAX_N], graphT[MAX_N], stock;
bool viz[MAX_N], add_m[MAX_N];
int  K, Nr, loc[MAX_N], muchii[2][MAX_N-1], extrem, gasit;


void citire()
{
    int x, y;
    freopen("plan.in", "r", stdin);
    freopen("plan.out", "w", stdout);
    scanf("%d%d", &N, &M);
    for(int i=1; i<=M; i++)
        {scanf("%d%d", &x, &y);
        graph[x].push_back(y);
        graphT[y].push_back(x);}
}

void dfs1(int x)
{
    viz[x]=true;
    if(graphT[x].size()!=0)
    {
        for(vector<int>::iterator it=graphT[x].begin(); it!=graphT[x].end(); it++)
            if(!viz[*it])
                dfs1(*it);
    }
    stock.push_back(x);
}

void dfs2(int x)
{
    viz[x]=true;
    if(graph[x].size()!=0)
    {
      for(vector<int>::iterator it=graph[x].begin(); it!=graph[x].end(); it++)
        if(!viz[*it])
            dfs2(*it);
    }

    loc[x]=K;
}

void dfs3(int x)
{
    viz[x]=true;
    if(graph[x].size()!=0)
       {
            for(vector<int>::iterator it=graph[x].begin(); it!=graph[x].end() && !gasit; it++)
                if(!viz[*it])
                    dfs3(*it);
       }
    if(!gasit)
        extrem=x;
    gasit=1;

}

void CompTareConexe()
{
    memset(viz, false, sizeof(viz));
    for(int i=1; i<=N; i++)
        if(!viz[i])
            dfs1(i);
    memset(viz, false, sizeof(viz));
    for(vector<int>::reverse_iterator it=stock.rbegin(); it!=stock.rend(); it++)
        if(!viz[*it])
        {dfs2(*it);
        K++;}
}

int main()
{
    int curent=0;
    citire();
    CompTareConexe();
    while(K!=1)
    {
        curent++; gasit=0; K=0;
        memset(viz, false, sizeof(viz));
        if(!add_m[curent])
            dfs3(curent);
        if(loc[extrem]!=loc[curent])
        {
            graph[extrem].push_back(curent);
            graphT[curent].push_back(extrem);
            muchii[1][Nr]=curent;
            muchii[0][Nr]=extrem;
            Nr++;
        }
        CompTareConexe();
    }
    printf("%d\n", Nr);
    for(int i=0; i<Nr; i++)
        printf("%d %d\n", muchii[0][i], muchii[1][i]);
    return 0;
}