This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll MOD = 1e9+7;
const int N = 1e3+5;
int n,m,mat[N][N],a[N][N];
vector<int>v[N],r[N];
void change(){
    for(int i=2;i<=n;i++){
        if(!mat[1][i]){
            for(int j=1;j<=n;j++){
                if(j==i)continue;
                mat[i][j]^=1;
                mat[j][i]^=1;
            }
        }
    }
}
void check(){
    bool ok=true;
    for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)if(!mat[i][j]&&i!=j)ok=false;
    if(ok){
        cout<<"DA";
        exit(0);
    }
}
int main()
{
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    cin>>n>>m;
    int x,y;
    while(m--){
        cin>>x>>y;
        mat[x][y]=1;
        mat[y][x]=1;
        a[x][y]=1;
        a[y][x]=1;
    }
    change();
    check();
    for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)mat[i][j]=a[i][j];
    for(int i=2;i<=n;i++){
        mat[1][i]^=1;
        mat[i][1]^=1;
    }
    change();
    check();
    cout<<"NE";
    return 0;
}
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