#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-8;
const double PI = acos(-1.0);
const long long int mod = 1e9 + 7;
const int MAXN = 1e6 + 5;
int dcmp(double a, double b) {
  return (fabs(a - b) < eps) ? 0 : (a < b ? -1 : +1);
}
void cp() {
  int n, w, m;
  cin >> n >> w >> m;
  cout << setprecision(10) << fixed;
  ;
  if (m > 2 * n) {
    cout << "NO\n";
    return;
  }
  double each = double(n * w) / double(m);
  double have = 0;
  vector<double> milk(n, w);
  vector<vector<pair<int, double>>> ans(1);
  bool excess = false;
  vector<int> freq(n + 1);
  while (((int)ans.size()) <= m && !milk.empty()) {
    double last = milk.back();
    milk.pop_back();
    double need = each - have;
    if (freq[((int)milk.size()) + 1] >= 2) excess = true;
    if (dcmp(need, last) > 0) {
      ans.back().push_back({((int)milk.size()) + 1, last});
      have += last;
    } else {
      last -= need;
      ans.back().push_back({((int)milk.size()) + 1, need});
      freq[((int)milk.size()) + 1]++;
      ans.push_back(vector<pair<int, double>>());
      if (dcmp(last, 0) > 0) milk.push_back(last);
      have = 0;
    }
  }
  if (((int)ans.size()) <= m || excess)
    cout << "NO\n";
  else {
    cout << "YES\n";
    for (auto &v : ans) {
      while (!v.empty()) {
        auto x = v.back();
        v.pop_back();
        while (!v.empty() && v.back().first == x.first)
          x.second += v.back().second, v.pop_back();
        cout << x.first << " " << x.second << " ";
      }
      cout << '\n';
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  int t;
  t = 1;
  while (t--) {
    cp();
  }
  return 0;
}
