#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9 + 7;
map<string, int> m;
string mmm[3003], mmmmm[3003];
map<pair<pair<int, int>, char>, int> mm;
int mmmm;
vector<string> ans;
string tos(int m) {
  string ret;
  for (int i = 0; i < 4; i++) ret += char('a' + m % 26), m /= 26;
  return ret;
}
string getname() {
  static int mmmmmm = 0;
  while (m.count(tos(mmmmmm))) mmmmmm++;
  return tos(mmmmmm++);
}
void M(int x) {
  if (mmmmm[x].size()) return;
  string s = mmm[x];
  if (isdigit(s[0])) {
    stringstream ss(s);
    int a, b;
    char op;
    ss >> a >> op >> b;
    M(a);
    M(b);
    if (x == m["res"])
      mmmmm[x] = "res";
    else
      mmmmm[x] = getname();
    ans.push_back(mmmmm[x] + '=' + mmmmm[a] + op + mmmmm[b]);
  } else {
    mmmmm[x] = s;
  }
}
int main() {
  std::ios::sync_with_stdio(0);
  std::cin.tie(0);
  ;
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    string a = s.substr(0, s.find("="));
    string b = s.substr(s.find("=") + 1);
    char op = 0;
    string ops = "$^#&";
    for (char c : ops)
      if (b.find(c) != string::npos) op = c;
    if (op) {
      string x = b.substr(0, b.find(op));
      string y = b.substr(b.find(op) + 1);
      if (!m.count(x)) {
        mmm[mmmm] = x;
        m[x] = mmmm++;
      }
      if (!m.count(y)) {
        mmm[mmmm] = y;
        m[y] = mmmm++;
      }
      pair<pair<int, int>, char> exp(pair<int, int>(m[x], m[y]), op);
      if (!mm.count(exp)) {
        mmm[mmmm] = to_string(m[x]) + op + to_string(m[y]);
        mm[exp] = mmmm++;
      }
      m[a] = mm[exp];
    } else {
      if (a == b) continue;
      if (!m.count(b)) {
        mmm[mmmm] = b;
        m[b] = mmmm++;
      }
      m[a] = m[b];
    }
  }
  if (!m.count("res")) {
    cout << 0 << endl;
    return 0;
  }
  M(m["res"]);
  if (ans.size() == 0) {
    if (mmmmm[m["res"]] == "res")
      cout << "0\n";
    else
      cout << "1\nres=" << mmmmm[m["res"]] << endl;
    return 0;
  }
  cout << ans.size() << endl;
  for (string s : ans) cout << s << endl;
}
