#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, v, m;
  cin >> n >> v >> m;
  vector<vector<pair<int, int> > > g(m);
  int c = 0;
  int d = m;
  int u = 0;
  for (int i = 0; i < m; i++) {
    int cur = n;
    while (cur > 0) {
      if (cur > d) {
        if (d > 0) g[i].push_back(make_pair(c, d));
        cur -= d;
        c++;
        d = m;
        u = 0;
      } else {
        g[i].push_back(make_pair(c, cur));
        d -= cur;
        cur = 0;
        u++;
        if (d > 0 && u > 1) {
          cout << "NO" << endl;
          return 0;
        }
      }
    }
  }
  cout << "YES" << endl;
  for (int i = 0; i < m; i++) {
    for (int j = 0; j < g[i].size(); j++) {
      if (j) cout << ' ';
      printf("%d %.10lf", g[i][j].first + 1, (double)g[i][j].second / m * v);
    }
    cout << endl;
  }
}
