#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, w, m;
  cin >> n >> w >> m;
  double Q = n * w / m;
  double rem = 0;
  bool f = 1;
  for (int i = 0; i < m; i++) {
    double q = Q;
    if (fabs(rem - q) < 1e-6) {
      q = 0;
      rem = 0;
    } else if (rem > q - 1e-6) {
      f = 0;
      break;
    }
    q -= rem;
    rem = 0;
    while (q + 1e-6 > w) q -= w;
    if (q > 1e-6) rem = w - q;
  }
  if (!f) {
    cout << "NO";
    return 0;
  }
  cout << "YES" << endl;
  int idx = 1;
  for (int i = 0; i < m; i++) {
    double q = Q;
    if (rem > 1e-6) {
      cout << idx++ << " " << fixed << setprecision(6) << rem << " ";
      q -= rem;
      rem = 0;
    }
    while (q + 1e-6 > w) {
      q -= w;
      cout << idx++ << " " << fixed << setprecision(6) << w << " ";
    }
    if (q > 1e-6) {
      cout << idx << " " << fixed << setprecision(6) << q << " ";
      rem = w - q;
    }
    cout << endl;
  }
  return 0;
}
