#include <bits/stdc++.h>
using namespace std;
long long n, w, m, cnt[110];
long double have[110], req[110];
long double lc = 1e-9;
vector<pair<long long, long double>> ans[110];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n >> w >> m;
  long double nn = n, mm = m, ww = w;
  for (int i = 1; i <= n; i++) {
    have[i] = w;
  }
  for (int i = 1; i <= m; i++) {
    req[i] = (nn / mm) * ww;
  }
  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (req[i] < lc) break;
      if (have[j] > lc) {
        long double tmp = min(have[j], req[i]);
        have[j] -= tmp;
        req[i] -= tmp;
        cnt[j]++;
        ans[i].push_back({j, tmp});
      }
    }
  }
  for (int i = 1; i <= m; i++) {
    if (req[i] > lc) {
      cout << "NO\n";
      return 0;
    }
  }
  for (int i = 1; i <= n; i++) {
    if (cnt[i] > 2) {
      cout << "NO\n";
      return 0;
    }
  }
  cout << "YES\n" << ' ' << fixed << setprecision(10) << ' ';
  for (int i = 1; i <= m; i++) {
    for (auto &it : ans[i]) {
      cout << it.first << ' ' << it.second << ' ';
    }
    cout << '\n';
  }
}
