#include <bits/stdc++.h>
using namespace std;
bool check(double a, double b) { return abs(a - b) < 1e-6; }
int main() {
  int n;
  while (cin >> n) {
    int w, m;
    cin >> w >> m;
    if (m > n * 2) {
      cout << "NO" << endl;
      continue;
    }
    double ave = n * w * 1.0 / m;
    stack<pair<double, int> > bottles;
    int used[55] = {0};
    vector<pair<int, double> > res[55];
    for (int i = 1; i <= n; i++) {
      bottles.push(make_pair((double)w, i));
    }
    bool flag = false;
    for (int i = 1; i <= m; i++) {
      if (flag) {
        break;
      }
      double t = ave;
      while (!check(t, 0)) {
        if (bottles.empty()) {
          cout << "NO" << endl;
          flag = true;
          break;
        }
        pair<double, int> bo = bottles.top();
        bottles.pop();
        if (bo.first >= t) {
          bo.first -= t;
          res[i].push_back(make_pair(bo.second, t));
          t = 0;
        } else {
          t -= bo.first;
          res[i].push_back(make_pair(bo.second, bo.first));
          bo.first = 0;
        }
        used[bo.second]++;
        if (used[bo.second] < 2 && bo.first > 0) {
          bottles.push(bo);
        }
      }
    }
    if (flag) {
      continue;
    }
    cout << "YES" << endl;
    for (int i = 1; i <= m; i++) {
      printf("%d %.6lf", res[i][0].first, res[i][0].second);
      for (int j = 1; j < res[i].size(); j++) {
        printf(" %d %.6lf", res[i][j].first, res[i][j].second);
      }
      puts("");
    }
  }
  return 0;
}
