#include <bits/stdc++.h>
using namespace std;
int n, w, m;
int main() {
  cin >> n >> w >> m;
  int all = w * m * n;
  int person = all / m, bot = all / n;
  bool flag = true;
  vector<vector<pair<int, int> > > p(m);
  for (int i = 0; i < (int)(n); ++i) {
    int s = i * bot, g = (i + 1) * bot;
    int sp = s / person, gp = g / person;
    if (g % person == 0) gp--;
    if (gp - sp + 1 >= 3) {
      flag = false;
      break;
    }
    if (sp == gp) {
      p[sp].push_back(pair<int, int>(i, g - s));
    } else {
      int mid = (sp + 1) * person;
      p[sp].push_back(pair<int, int>(i, mid - s));
      p[gp].push_back(pair<int, int>(i, g - mid));
    }
  }
  if (not flag) {
    cout << "NO";
  } else {
    cout << "YES" << endl;
    for (__typeof((p).begin()) i = (p).begin(); i != (p).end(); ++i) {
      vector<pair<int, int> > &v = *i;
      for (__typeof((v).begin()) it = (v).begin(); it != (v).end(); ++it) {
        if (it->second > 0) {
          printf("%d %.8f ", it->first + 1, (double)(it->second) / m);
        }
      }
      cout << endl;
    }
  }
  return 0;
}
