#include <bits/stdc++.h>
using namespace std;
mt19937 rnd(339264);
const long long MOD = 998244353;
const double eps = 1e-7;
int main() {
  cout << fixed << setprecision(20);
  int n, w, m;
  cin >> n >> w >> m;
  if (2 * n < m) {
    cout << "NO";
    return 0;
  }
  int left = m;
  int j = 0;
  vector<vector<pair<int, int>>> ans(m);
  for (int i = 0; i < m; i++) {
    int need = n;
    if (left < m && left > n) {
      cout << "NO";
      return 0;
    }
    while (need >= left) {
      ans[i].push_back({j, left});
      need -= left;
      left = m;
      j++;
    }
    if (need > 0) {
      ans[i].push_back({j, need});
      left -= need;
    }
  }
  cout << "YES" << endl;
  for (int i = 0; i < m; i++) {
    for (auto &p : ans[i]) {
      cout << p.first + 1 << " " << (p.second * w) / ((double)m) << " ";
    }
    cout << endl;
  }
  return 0;
}
