// editor3
#include<stdio.h>
void transposeGraph(int edges[][2],int m){
    for(int i=0;i<m;i++){
        printf("%d %d",edges[i][1],edges[i][0]);
        if(i!=m-1)
        printf("\n");
    }
    
}
int main(){
    int n,m;
    scanf("%d %d",&n,&m);
    if(n<0 || m<0){
        printf(Invalid Input);
        return 0;
    }
    int edges[m][2];
    for(int i=0;i<m;i++){
        scanf("%d %d",&edges[i][0],&edges[i][1]);
    }
    transposeGraph(edges,m);
    return 0;
}