#include <bits/stdc++.h>
using namespace std;
vector<pair<int, double>> ans[52];
int main() {
  int n, w, m;
  cin >> n >> w >> m;
  double s = (n * w) / (m * 1.0), c = w, b = 1, k = 0;
  for (int i = 0; i < m; i++) {
    double ne = s;
    while (1) {
      if (ne + 10e-7 > c) {
        ans[i].push_back(make_pair(b, c));
        ne -= c;
        c = w;
        b++;
        if (++k > 2) {
          cout << "NO";
          return 0;
        }
        k = 0;
        if (abs(ne) < 10e-7) break;
      } else {
        ans[i].push_back(make_pair(b, ne));
        c -= ne;
        k++;
        break;
      }
    }
  }
  cout << "YES\n";
  for (int i = 0; i < m; i++) {
    for (auto it : ans[i])
      cout << fixed << setprecision(0) << it.first << " " << setprecision(6)
           << it.second << " ";
    cout << "\n";
  }
  return 0;
}
