#include <bits/stdc++.h>
using namespace std;
int n, w, m;
vector<pair<int, double> > v[55];
int main() {
  cin >> n >> w >> m;
  double sum = w * n / double(m);
  double curCup = 0.0;
  int cur = 0;
  for (int i = 0; i < n; ++i) {
    double curMilk = w;
    if (curCup + curMilk - 1e-6 > sum) {
      v[cur].push_back(make_pair(i, sum - curCup));
      curMilk -= sum - curCup;
      if (curMilk - 1e-6 > sum) {
        cout << "NO" << endl;
        return 0;
      }
      ++cur;
      if (cur == m) {
        cout << "NO" << endl;
        return 0;
      }
      curCup = curMilk;
      v[cur].push_back(make_pair(i, curMilk));
      if (fabs(curCup - sum) < 1e-6) {
        ++cur;
        curCup = 0;
        if (cur == m + 1) {
          cout << "NO" << endl;
          return 0;
        }
      }
    } else {
      curCup += curMilk;
      v[cur].push_back(make_pair(i, curMilk));
      if (fabs(curCup - sum) < 1e-6) {
        ++cur;
        curCup = 0;
        if (cur == m + 1) {
          cout << "NO" << endl;
          return 0;
        }
      }
    }
  }
  cout << "YES" << endl;
  for (int i = 0; i < m; ++i) {
    for (int j = 0; j < v[i].size(); ++j)
      printf("%d %.6lf ", v[i][j].first + 1, v[i][j].second);
    printf("\n");
  }
  return 0;
}
