#include <bits/stdc++.h>
using namespace std;
const long long INF = (long long)1e15;
int n, w, m;
vector<pair<int, double> > ans[2000];
int main() {
  double each, left, cur;
  int i, j, c;
  cin >> n >> w >> m;
  each = (n * w) * 1. / m;
  left = w;
  j = c = 1;
  for (i = 1; i <= m; ++i) {
    cur = each;
    while (cur > 1e-8) {
      if (left < 1e-8) left = w, ++j, c = 1;
      if (left >= cur)
        left -= cur, ans[i].push_back(make_pair(j, cur)), cur = 0, ++c;
      else
        cur -= left, ans[i].push_back(make_pair(j, left)), left = 0, ++c;
      if (left > 1e-8 && c > 2) {
        cout << "NO" << endl;
        return 0;
      }
    }
    cur = 0;
  }
  cout << "YES" << endl;
  for (i = 1; i <= m; ++i) {
    for (j = 0; j < (int)ans[i].size(); ++j)
      printf("%d %.7f ", ans[i][j].first, ans[i][j].second);
    printf("\n");
  }
}
