func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, m, x, y, k, T, p[300], a[300][300];   void dfs(int i) {     for (int j = 0; j <= n; j++)       if (a[i][j]) {         a[i][j] = a[j][i] = 0;         p[i]--;         p[j]--;         if (j && i) cout << j <<     << i << endl;         dfs(j);       }   }   int main() {     ios::sync_with_stdio(false);     cin >> T;     for (int t = 0; t < T; t++) {       cin >> n >> m;       for (int i = 0; i <= n; i++)         for (int j = 0; j <= n; j++) a[i][j] = 0, p[i] = 0;       for (int i = 0; i < m; i++)         cin >> x >> y, a[x][y]++, a[y][x]++, p[x]++, p[y]++;       k = 0;       for (int i = 1; i <= n; i++)         if (p[i] & 1)           a[0][i] = a[i][0] = 1;         else           k++;       cout << k << endl;       for (int i = 1; i <= n; i++)         if (p[i]) dfs(i);     }     return 0;   }   