#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  double w;
  while (cin >> n >> w >> m) {
    double k = 1.0 * n * w / m;
    int b = 0, cnt = 0, ok = 1;
    double left = w;
    vector<pair<int, double> > V[m];
    for (int i = 0; i < m; i++) {
      double tmp = 0;
      while (fabs(tmp - k) > 1e-8) {
        double v = min(k - tmp, left);
        tmp += v;
        V[i].push_back(make_pair(b, v));
        if (abs(left - v) < 1e-8) {
          b++;
          cnt = 0;
          left = w;
        } else {
          left -= v;
          cnt++;
        }
        if (cnt == 2) {
          ok = 0;
          break;
        }
      }
    }
    if (ok) {
      cout << "YES" << endl;
      for (int i = 0; i < m; i++) {
        for (int j = 0; j < V[i].size(); j++) {
          if (j > 0) printf(" ");
          printf("%d %.6lf", V[i][j].first + 1, V[i][j].second);
        }
        cout << endl;
      }
    } else
      cout << "NO" << endl;
  }
  return 0;
}
