#include <bits/stdc++.h>
using namespace std;
long long a[1010];
long long b[1000];
long long us[1010];
vector<pair<long long, long long> > v[100010];
int main() {
  long long n, i, w, m, s, l, r;
  cin >> n >> w >> m;
  s = n * w;
  w *= m;
  for (i = 1; i <= n; i++) a[i] = w;
  for (i = 1; i <= m; i++) b[i] = s;
  if (w > s * 2) {
    cout << "NO";
    return 0;
  }
  l = 1, r = 1;
  while (l != m + 1 && r != n + 1) {
    if (us[r] >= 2) {
      cout << "NO\n";
      return 0;
    }
    us[r]++;
    if (a[r] == b[l])
      v[l].push_back({r, a[r]}), l++, r++;
    else if (a[r] > b[l])
      a[r] -= b[l], v[l].push_back({r, b[l]}), l++;
    else
      b[l] -= a[r], v[l].push_back({r, a[r]}), r++;
  }
  if (r != n + 1 || l != m + 1) {
    cout << "NO";
    return 0;
  }
  cout << "YES\n";
  for (i = 1; i <= m; i++) {
    for (int j = 0; j < v[i].size(); j++) {
      cout << v[i][j].first << ' ';
      double tt = (v[i][j].second * 1.0) / (m * 1.0);
      printf("%.7f ", tt);
    }
    cout << '\n';
  }
}
