func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, m, fs[100010], to[300010], nx[300010], e, sz[300010], as, bs, l[300010],       op, ed, yoo, aya, ans[100010];   bool p[100010], done[100010], q[100010], r[100010];   void ins(int x, int y) {     nx[++e] = fs[x];     fs[x] = e;     to[e] = y;     nx[++e] = fs[y];     fs[y] = e;     to[e] = x;   }   int main() {     cin >> n >> m;     for (int i = 1, x, y; i <= m; ++i) {       cin >> x >> y;       ins(x, y);       sz[x]++;       sz[y]++;     }     for (int i = 1; i <= n; ++i)       if (!done[i]) {         for (done[l[op = ed = 0] = i] = 1; op <= ed; ++op)           for (int v = fs[l[op]]; v; v = nx[v])             if (!done[to[v]]) {               done[to[v]] = 1;               p[to[v]] = p[l[op]] ^ 1;               l[++ed] = to[v];             }       }     for (int i = 1; i <= n; ++i)       if (!p[i])         as++;       else         bs++;     if (as % 3 == 0) {       cout <<  YES  << endl;       int out = 0;       for (int i = 1; i <= n; ++i)         if (p[i]) ans[i] = (out++) / 3 + 1;       for (int i = 1; i <= n; ++i)         if (!p[i]) ans[i] = (out++) / 3 + 1;       for (int i = 1; i <= n; ++i) cout << ans[i] <<    ;       cout << endl;       return 0;     }     if (as % 3 == 2) {       for (int i = 1; i <= n; ++i) p[i] ^= 1;       swap(as, bs);     }     for (int i = 1; i <= n; ++i)       if (!p[i]) {         if (sz[i] <= bs - 2) {           cout <<  YES  << endl;           int out = 3;           ans[i] = 1;           for (int v = fs[i]; v; v = nx[v])             if (p[to[v]]) q[to[v]] = 1;           for (int j = 1, k = 0; j <= n && k < 2; ++j)             if (p[j] && !q[j]) {               ans[j] = 1;               k++;             }           for (int j = 1; j <= n; ++j)             if (!p[j] && j != i) ans[j] = (out++) / 3 + 1;           for (int j = 1; j <= n; ++j)             if (p[j] && ans[j] != 1) ans[j] = (out++) / 3 + 1;           for (int j = 1; j <= n; ++j) cout << ans[j] <<    ;           cout << endl;           return 0;         }       }     memset(q, 0, sizeof q);     for (int i = 1; i <= n; ++i)       if (p[i] && (yoo == 0 || as - sz[i] > as - sz[yoo])) yoo = i;     for (int v = fs[yoo]; v; v = nx[v]) q[to[v]] = 1;     int opt = 0;     for (int i = 1; i <= n; ++i)       if (p[i] && i != yoo && as - sz[i] >= 2) {         int c = 0, a = as - sz[yoo], b = as - sz[i];         for (int v = fs[i]; v; v = nx[v])           if (!q[to[v]]) c++;         c = a - c;         if (a >= 2 && b >= 2 && a + b - c >= 4) {           int out = 6, k = 0;           cout <<  YES  << endl;           for (int v = fs[i]; v; v = nx[v]) r[to[v]] = 1;           ans[i] = 1;           for (int j = 1; j <= n && k < 2; ++j)             if (!p[j] && !r[j] && q[j]) {               ans[j] = 1;               k++;             }           for (int j = 1; j <= n && k < 2; ++j)             if (!p[j] && !r[j]) {               ans[j] = 1;               k++;             }           k = 0;           ans[yoo] = 2;           for (int j = 1; j <= n && k < 2; ++j)             if (!p[j] && !q[j] && !ans[j]) {               ans[j] = 2;               k++;             }           for (int j = 1; j <= n; ++j)             if (!p[j] && !ans[j]) ans[j] = (out++) / 3 + 1;           for (int j = 1; j <= n; ++j)             if (p[j] && !ans[j]) ans[j] = (out++) / 3 + 1;           for (int j = 1; j <= n; ++j) cout << ans[j] <<    ;           cout << endl;           return 0;         }       }     cout <<  NO  << endl;     return 0;   }   