func_code_string: #include <bits/stdc++.h>   using namespace std;   typedef int nod[100010];   typedef int edg[200010];   int n, m;   int e = 1;   nod h;   edg link, v, u;   nod vis;   nod fz;   int ju;   void creat(int x, int y) {     link[++e] = h[x];     h[x] = e;     v[e] = y;     link[++e] = h[y];     h[y] = e;     v[e] = x;   }   int dfs(int x) {     if (vis[x])       return 0;     else       vis[x] = 1;     for (int i = h[x]; i; i = link[i])       if (!u[i]) {         u[i] = u[i ^ 1] = 1;         if ((ju = dfs(v[i])))           printf( %d %d %d n , x, v[i], ju);         else if (!fz[x])           fz[x] = v[i];         else           printf( %d %d %d n , fz[x], x, v[i]), fz[x] = 0;       }     return fz[x];   }   int main() {     scanf( %d%d , &n, &m);     if (m & 1) {       printf( No solution n );       return 0;     }     for (int i = 1, x, y; i <= m; ++i) scanf( %d%d , &x, &y), creat(x, y);     dfs(1);     return 0;   }   